Fuji Power MOSFET Fuji Power MOSFET PowerMOSFET Application Note '11-4 Fuji Electric Co.,Ltd. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 1 Fuji Power MOSFET WARNING 1. This Catalog contains the product specifications, characteristics, data, materials, and structures as of April 2011. The contents are subject to change without notice for specification changes or other reasons. When using a product listed in this Catalog, be sure to obtain the latest specifications. 2. All applications described in this Catalog exemplify the use of Fuji's products for your reference only. No right or license, either express or implied, under any patent, copyright, trade secret or other intellectual property right owned by Fuji Electric Co., Ltd.is (or shall be deemed) granted. Fuji Electric Co., Ltd. makes no representation or warranty, whether express or implied, relating to the infringement or alleged infringement of other's intellectual property rights which may arise from the use of the applications described herein. 3. Although Fuji Electric Co., Ltd. is enhancing product quality and reliability, a small percentage of semiconductor products may become faulty. When using Fuji Electric semiconductor products in your equipment, you are requested to take adequate safety measures to prevent the equipment from causing a physical injury, fire, or other problem if any of the product become faulty. It is recommended to make your design fail-safe, flame retardant, and free of malfunction. 4. The products introduced in this Catalog are intended for use in the following electronic and electrical equipment which has normal reliability requirements. * Computers * OA equipment * Machine tools * Audiovisual equipment * Communications equipment (terminal devices) * Measurement equipment * Electrical home appliances * Industrial robots etc. * Personal equipment 5. If you need to use a product in this Catalog for equipment requiring higher reliability than normal, such as for the equipment listed below, it is imperative to contact Fuji Electric Systems Co., Ltd. to obtain prior approval. When using these products for such equipment, take adequate measures such as a backup system to prevent the equipment from malfunctioning even if a Fuji's product incorporated in the equipment becomes faulty. * Transportation equipment (mounted on cars and ships) * Trunk communications equipment * Traffic-signal control equipment * Gas leakage detectors with an auto-shut-off feature * Emergency equipment for responding to disasters and anti-burglary devices * Safety devices * Medical equipment 6. Do not use products in this Catalog for the equipment requiring strict reliability such as the following and equivalents to strategic equipment (without limitation). * Space equipment * Aeronautic equipment * Nuclear control equipment * Submarine repeater equipment 7. Copyright (c)1996-2008 by Fuji Electric Systems Co., Ltd. All rights reserved. No part of this Catalog may be reproduced in any form or by any means without the express permission of Fuji Electric Co., Ltd. 8. If you have any question about any portion in this Catalog, ask Fuji Electric Co., Ltd. or its sales agents before using the product. Neither Fuji Electric Co., Ltd. nor its agents shall be liable for any injury caused by any use of the products not in accordance with instructions set forth herein. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 2 Fuji Power MOSFET Contents 1. Structure and features of the device 2. Terms and characteristics 3. Circuit design and device characteristics 4. Circuit design and mechanism of breakdown 5. Thermal design 6. Cautions in mounting and handling 7. Application to switching power supply ...... ...... ...... ...... ...... ...... ...... 4 7 11 19 25 31 36 Note: * The contents of this document are subject to change without prior notice because of product improvement, etc. * The applications and the parts constants listed in this document is for assisting the design, and does not take the variation of parts and operating conditions into consideration. When integrating our products into your design, take the variation of these parts and operating conditions into consideration. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 3 Fuji Power MOSFET 1. Structure and features of the device 1-1. Structure and features of the device Just as the name suggests, a Power MOSFET is a semiconductor device in a metal-oxide semiconductor (MOS) structure operating due to the field effect. Of the two types of Power MOSFET (vertical and horizontal types), the vertical type has a feature that current is fed over the entire chip and the resistance per unit chip area (ON resistance, which is the most important characteristics of the MOSFET) can be minimized. Compared with conventional bipolar transistors, the Power MOSFET has the following advantages: 1) Since it is a voltage-controlled device, drive power is low. 2) Since it is a unipolar device, high-speed switching is allowed. 3) Since the temperature coefficient of the current is negative, no secondary breakdown occurs, which facilitates parallel operation. Fig.1-1 Basic structure of the Power MOSFET Figure 1-2 shows the cross-sectional view of a SuperFAP series chip, whereas Fig. 1-3 shows that of a conventional chip. The SuperFAP series feature the following: 1) Reduced turnoff power dissipation 2) Reduced gate charge 3) Low RonA The SuperFAP series contributes to the reduction of power dissipation, improvement of efficiency, and downsizing. Gate G a te S o u rc e Source Gate G a te C G D CGD DDrain ra in Drain D ra in Fig.1-2 Cross-sectional view of a SuperFAP series chip Fig.1-3 Cross-sectional view of a conventional chip Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 Source S o u rc e 4 Fuji Power MOSFET 1-2. Power MOSFET of Fuji Electric Systems Co., Ltd. Since 1982, Fuji Electric Systems Co., Ltd. has been importing Power MOSFET elements from Siemens AG in the Federal Republic of Germany, assembling them, and providing the assemblies to the market. Fuji has also established an integrated production system ranging from wafer process to assembly through technical partnership with Siemens entered in 1986, and started mass-producing Power MOSFETs. We then focused on improving the properties to achieve ultrahigh-speed switching and high avalanche capacity, and are now providing our products mainly in the field of switching power supplies. Figure 1-4 shows the Power MOSFET series developed by us. High-voltage Power MOSFET Low-voltage Power MOSFET 1980 SIPMOS (F-0) F- 1990 F- F- F- FAP- FAP- FAP-A FAP-A FAP-S series series 1995 FAP-B series Trench FT-1 2000 series SuperFAP-G SuperFAP-G series series Trench FT-2 series SuperFAP-E3 2010 series Super Junction MOSFET Fig.1-4 Fuji Power MOSFET series Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 5 Fuji Power MOSFET 1-3. Code symbols of Fuji Power MOSFET FM V 06 N 60 ES (1) (2) (3) (4) (5) (6) (6)Code of Series category (1)Code of Device type F: Fuji Electric M: MOSFET Code Series Blank Conventional series product (2)Code of Package Outline G GF SuperFAP-G SuperFAP-G (FRED) Code A Package TO-220F T2 E Trench MOSFET (2G) SuperFAP-E3 B C D H D2-Pack T-Pack(S) K-Pack(S) TO-3P(Q) ES SuperFAP-E3S S1 SJ-MOSFET (1G) I K L T-Pack(L) TO-3PL TFP P R U V W TO-220AB TO-3PF K-Pack(L) TO-220F(SLS) TO-247 (5)Drain-Source Voltage rating range 1/10 of drain-source withstand voltage VDSS[V] (4)Code of Polarity N: N-Channnel MOSFET P: P-Channnel MOSFET (3)Current rating range Drain current ID [A] 2SK 3686 -01 (1) (2) (3) (1)Code of Device type 2SK: N-Channnel MOSFET 2SJ: P-Channnel MOSFET (3)Avalanche Proof -01: Avalanche Proven product (2)JEITA registration number Serial number Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 6 Fuji Power MOSFET 2. Terms and characteristics 2-1. Description of terms (Absolute maximum rating, electrical characteristics) 2-1-1. Absolute maximum rating (Reference example) Excerpt from the specification of the FMV06N60ES 5.Absolute Maximum Ratings at Tc=25C (unless otherwise specified) Description Symbol Drain-Source Voltage Characteristics Unit VDS 600 V VDSX 600 V Remarks Note *1 : Tch150, See Fig.1 and Fig.2 Note *2 : Stating Tch=25, IAS=2.4A, L=99.8mH, Vcc=60V, RG=50, See Fig.1 and Fig.2 Continuous Drain Current ID 6 A Pulsed Drain Current IDP 24 A EAS limited by maximum channel temperature and avalanche current. See to 'Avalanche Energy' graph of page 9/15. Note *3 : Repetitive rating : Pulse width limited by maximum channel temperature. See to the 'Transient Themal impeadance' graph of page 9/15. Note *4 : IF -ID , -di/dt=100A/s, VccBVDSS, Tch150. Gate-Source Voltage VGS 30 V Note *5 : IF -ID , dv/dt=3.8kV/s, VccBVDSS, Tch150. IAR 6 A Note *1 EAS 313.7 mJ Note *2 EAR 3.7 mJ Note *3 Repetitive and Non-Repetitive Maximum Avalanche Current Non-Repetitive Maximum Avalanche Energy Repetitive Maximum Avalanche Energy VGS=-30V Peak Diode Recovery dV/dt dV/dt 3.8 kV/s Note *4 Peak Diode Recovery -di/dt -di/dt 100 A/s Note *5 Maximum Power Dissipation PD Operating and Storage T ch 150 Temperature range T stg -55 to +150 Isolation Voltage VISO 2 kVrms Term 2.16 W 37 Ta=25 Tc=25 t=60sec,f=60Hz Symbol Drain-Source Voltage VDSS Definition and description Maximum voltage value permitted between the drain and the source in a state where the gate and the source are short-circuited. Maximum DC current value permitted to the drain terminal determined based on the Continuous Drain current ID maximum power dissipation and the maximum ON resistance (Tch=150deg.) . (including forward current rating of parasitic diodes) Maximum peak value of the drain current permitted at the time of pulse operation at pulse Pulsed Drain Current ID pulse width and duty ratio specified in the "area of safe operation" of the characteristic curve. Specified as 4 times the continuous drain current. Gate-Source Voltage VGS Repetitive and Non-Repetitive Maximum Avalanche Current IAR Maximum voltage value permitted between the gate and the source. Maximum permitted voltage value of the gate oxide film. Maximum permitted current at the occurrence of an avalanche. Forward current value of the avalanche parasitic diode. Maximum Avalanche Energy Non-Repetitive EAS Repetitive EAR Peak Diode Recovery dV/dt dv/dt Peak Diode Recovery -di/dt -di/dt Maximum permissible power at the occurrence of an avalanche. Rate of change of the maximum permissible D-S voltage during reverse recovery operation of the parasitic diode Rate of change of the maximum permissible D-S current during reverse recovery operation of the parasitic diode Maximum Power Dissipation Independent use state (Ta=25deg.) PD Maximum power dissipation value permitted to the MOSFET. Infinite heat dissipated state (Tc=25deg.) Channel temperature Tch Storage temperature Tstg Isolation Voltage VISO Chip temperature range in which MOSFET operation is permitted Temperature range allowing storage or transportation of the MOSFET without being subjected to electric load Applicable to full-mold packages only * Derating is required for some absolute maximum rating items depending on conditions such as case temperature. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 7 Fuji Power MOSFET 2-1-2. Electrical characteristics (Static Ratings) (Reference example) Excerpt from the specification of the FMV06N60ES 6.Electrical Characteristics at Tc=25C (unless otherwise specified) Static Ratings Description Symbol Drain-Source Conditions min. typ. max. Unit 600 - - V 3.2 3.7 4.2 V T ch=25 - - 25 T ch=125 - - 250 - 10 100 nA - 1.03 1.20 ID =250A Breakdown Voltage BVDSS Gate Threshold VGS=0V ID =250A Voltage VGS(th) Zero Gate Voltage Drain Current IDSS Gate-Source Leakage Current IGSS Drain-Source On-State Resistance RDS(on) Term Drain-Source Breakdown Voltage Gate Threshold Voltage Zero Gate Voltage Drain Current Gate-Source Leakage Current Drain-Source On-State Resistance VDS=VGS VDS=600V VGS=0V VDS=480V VGS=0V A VGS= 30V VDS=0V ID =3A VGS=10V Symbol Definition and description Breakdown voltage between the drain and the source (= Reverse voltage of the parasitic diode). BVDSS Voltage value between the drain and the source measured with specified drain current fed, in a state where the gate and the source are short-circuited. VGS(th) Gate voltage value allowing the drain current to start flowing. Gate source voltage value measured by feeding specified drain current and applying specified drain source voltage. Current between the drain and the source when the gate voltage is 0V (= Drain leakage current). IDSS Drain current value measured by applying specified drain-source voltage in a state where the gate and the source are short-circuited. IGSS RDS(on) Gate leakage current value measured by applying specified gate-source voltage in a state where the drain and the source are short-circuited. Resistance between the drain and the source measured by applying specified gate-source voltage and feeding specified drain current. * Unless otherwise specified, the above characteristics are exhibited when at Tc=25deg. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 8 Fuji Power MOSFET 2-1-3. Electrical characteristics (Dynamic Ratings) (Reference example) Excerpt from the specification of the FMV06N60ES Dynamic Ratings Description Symbol Forward Conditions min. typ. max. Unit S ID =3.0A Transconductance gf s VDS=25V 2.5 5 - Input Capacitance Ciss VDS=25V - 950 1425 Output Capacitance Coss VGS=0V - 100 150 f=1MHz - 7.5 11 Reverse Transfer pF Capacitance Crss Turn-On Time td(on) Vcc =300V ID =3.0A - 29 43.5 tr VGS=10V RGS=27 - 15 22.5 td(off) See Fig.3 and Fig.4 - 75 113 - 16 24 Turn-Off Time tf Total Gate Charge QG Vcc =300V - 31 46.5 Gate-Source Charge QGS VGS=10V - 10.5 15.8 Gate-Drain Charge QGD See Fig.5 - 8 12 Gate-Drain Crossover Charge QSW - 4.5 6.75 Term Forward Transconductance ID =6A Symbol ns nC Definition and description Rate of change of the drain current against the specified change in gate-source voltage measured gfs by applying specified drain-source voltage and feeding specified drain current. Represents the degree of ease of feeding current. Equivalent to hFE of bipolar transistors. Characteristic value of the parasitic capacitance measured between gate and source terminals at Input Capacitance Ciss specified gate-source and drain-source voltage and measuring frequency, in a state where the drain and the source are alternately short-circuited. Characteristic value of the parasitic capacitance measured between drain and source terminals at Output Capacitance Coss specified gate-source and drain-source voltage and measuring frequency, in a state where the gate and the source are alternately short-circuited. Reverse Transfer Capacitance Characteristic value of the parasitic capacitance measured between the drain and the gate at Crss specified gate-source voltage and measuring frequency in a state where source terminal is grounded. Turn-On Delay Time td(on) Turn-On Time tr Turn-Off Delay Time td(off) Turn-Off Time tf Total Gate Charge QG Gate-Source Charge QGS Delay time of drain voltage with respect to the gate voltage measured between 10% value of gate-source voltage and 90% value of drain-source voltage. Time required for drain voltage measured between 90% value and 10% value of the drain-source voltage to decrease. Delay time of drain voltage with respect to the gate voltage measured between 90% value of gate-source voltage and 10% value of drain-source voltage. Time required for the drain voltage measured between 10% value and 90% value of drain-source voltage to increase. Gate charge required to turn on the MOSFET VGS Mirror effect area (=QGD) ID VGS(on) Gate-Drain Charge QGD VGS(th) VDS Period where VDS and ID Gate-Drain Crossover Charge QSW ID starts to flow at VGS(th) QGS QGD QSW QG Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 9 are crossing (=QSW) Fuji Power MOSFET 2-1-4. Electrical characteristics (Parasitic diode) (Reference example) Excerpt from the specification of the FMV06N60ES Reverse Diode Description Symbol Avalanche Capability Conditions min. typ. max. Unit 6 - - A - 0.90 1.35 V - 0.4 - s - 3.3 - C L=6.39mH Tch=25 IAV See Fig.1 and Fig.2 IF =6A Diode Forward On-Voltage VSD Reverse Recovery Time trr Reverse Recovery VGS=0V T ch=25 IF =6A VGS=0V -di/dt=100A/s, Tch=25 See Fig.6 Charge Qrr Term Symbol Definition and description Drain current value resistant to the switching of unclamped inductance. Since the current is fed Avalanche Capability IAV at the parasitic pn contact (parasitic diode structure), the avalanche capacity is displayed as parasitic diode characteristics. Same as avalanche current at absolute maximum rating. Forward voltage between the source and the drain measured by feeding forward current IF to the Diode Forward On-Voltage VSD parasitic diode at gate voltage VGS=0V and chip temperature Tch=25deg. When forward bias voltage is applied to the gate terminal, current is fed to the parasitic diode and the MOSFET. Consequently, this value decreases (Synchronous rectification). Time required for reverse recovery current of Reverse Recovery Time trr parasitic diode to vanish under specified measurement conditions. The same switching characteristics as diodes for input bridge. Reverse Recovery Charge Qrr Slow compared with fast recovery diodes. FRED type is high-speed parasitic diode. 2-1-5. Electrical characteristics (Thermal resistance) (Reference example) Excerpt from the specification of the FMV06N60ES 7.Thermal Resistance Description Channel to Case Channel to Ambient Symbol min. Rth(ch-c) Rth(ch-a) Term typ. max. Unit 3.38 58.0 /W /W Symbol Definition and description Thermal resistance from the channel to the surface of the case of the device (heat sink mounting Thermal Resistance (Channel to Case) Rth(ch-c) surface). The characteristics depend on package and chip sizes. The larger the chip size, the smaller the thermal resistance. Use this value to calculate thermal resistance at the time of mounting the heat sink. Thermal resistance from the channel to the ambient. Thermal resistance from the chip to the Thermal Resistance (Channel to Ambient) ambient not affected by temperature increase measured in an independent state where heat Rth(ch-a) sink, etc. are not mounted. The characteristics become a unique value depending on packages. Thermal resistance in a state mounted to specified substrate may be adopted for SDM packages, etc. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 10 Fuji Power MOSFET 3. Circuit design and device characteristics 3-1. Drain-Source Breakdown Voltage : BVDSS The drain-source breakdown voltage BVDSS for guaranteeing rated voltage is specified in min. value. To ensure safety in circuit operation with respect to this guaranteed value, a margin is allowed for actual value. However, since the drain-source breakdown voltage and ON resistance is in a trade-off relation, by decreasing the margin as far as possible, the ON resistance is decreased. The dependence of the drain-source breakdown voltage on temperature exhibits positive temperature dependence, and generally increases at the rate of 10%/100deg. 3-2. Gate Threshold Voltage : VGS(th) The gate threshold voltage is the gate-source voltage VGS allowing the MOSFET to start feeding current. Figure 3-1 is a temperature characteristics chart of the gate-source threshold voltage VGS(th). The gate-source threshold voltage has different negative temperature coefficient (-5mV to -7mV/deg.) depending on products, and decreases under the high-temperature condition, namely the actual operating conditions. Consequently, when designing a drive circuit, it is necessary to check the temperature characteristics chart of the gate-source threshold value listed in the data sheet to prevent malfunction from occurring due to external noise, etc. Figure 3-2 is a chart demonstrating the transmission characteristics of the gate voltage VGS and the drain current ID. In the MOSFET, the current fed by the gate voltage is limited. Consequently, when designing a drive circuit, it is necessary to check the transmission characteristics chart of the gate voltage and drain voltage listed in the data sheet to set a gate voltage that can feed sufficient drain current. If the gate voltage is set low to minimize drive power dissipation, required drain current cannot be fed, and consequently required output cannot be obtained. In addition, increase in ON dissipation may result in a breakdown. Typical Transfer Characteristic ID=f(VGS):80 s pulse test,VDS=25V,Tch=25 C Gate Threshold Voltage vs. Tch VGS(th)=f(Tch):VDS=VGS,ID=250A 8 100 7 When drain current ID=5A is fed, gate voltage VGS=5.9V or higher is required. 6 5 ID[A] VGS(th) [V] 10 max. 4 typ. 1 3 min. 2 1 0.1 0 -50 -25 0 25 50 75 Tch [C] 100 125 0 150 Fig.3-1 VGS(th) temperature characteristics chart 1 2 3 4 5 VGS[V] 6 7 8 9 10 Fig.3-2 VGS-ID transmission characteristics chart 3-3. Zero Gate Voltage Drain Current (Drain Leakage Current) : IDSS The zero gate voltage drain current is a leakage current between the drain and the source. The drain leakage current has positive temperature characteristics. The dissipation from IDSS is expressed by P(IDSS)=VDS IDSS when the MOSFET remains OFF. However, within normal operating range, the value is negligibly small compared with the ON dissipation (dissipation generated by RDS(on)). Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 11 Fuji Power MOSFET 3-4. Maximum Power Dissipation : PD Figure 3-3 is a chart showing the reduction curve of the maximum power dissipation PD at the case temperature Tc under the condition of absolute maximum rating of the channel temperature Tch=150deg. In designing, it is essential not to allow the power dissipation PD to be exceeded at the assumed maximum case temperature Tc. Note that the power dissipation PD listed in the brochure and the data sheet is the value calculated from the heat resistance between the channel and the case Rth(ch-c) in a state where the device is mounted to an infinite radiator plate. The power dissipation in actual operation is calculated from the thermal resistance and ambient temperature, with the thermal resistance of the heat sink to be mounted and contact thermal resistance taken into Allowable Power Dissipation consideration. PD=f(Tc) 40 Power dissipation on the data sheet: Infinite heat dissipated state PD 35 Tch(max) Tc [W ] Rth(ch c) 30 PD Tch(max) Ta [W ] Rth(ch c) Rth(c f ) Rth( f a ) PD [W] 25 Power dissipation in actual operation: (Example) State in which a heat sink is mounted 20 15 10 Rth(c-f) : Contact thermal resistance with the heat sink Rth(f-a) : Thermal resistance of the heat sink Ta : Ambient temperature Tc : Case temperature 5 0 0 25 50 75 100 125 150 Tc [C] Fig.3-3 Power dissipation PD temperature 3-5. Thermal Resistance (Channel to Case) : Rth(ch-c) characteristics chart The thermal resistance value listed in the brochure or the data sheet is the thermal resistance in steady state. When preparing thermal design of devices that perform pulse operation such as switching power supply, or calculating the temperature increase due to pulse surge, it is necessary to find the thermal resistance at any given time from the transient thermal impedance characteristics chart (Fig.3-4) listed in the data sheet, or to use a calculated value. Maximum Transient Thermal Impedance Zth(ch-c)=f(t):D=0 1 10 0 Zth(ch-c) [C/W] 10 Transient region -1 10 Constant region -2 10 -3 10 -6 10 -5 10 -4 10 -3 -2 10 10 -1 10 t [sec] Fig.3-4 Transient resistance characteristics chart Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 12 0 10 Fuji Power MOSFET 3-6. Area of safe operation (ASO) Figure 3-5 shows the area of safe operation of the FMV06N60ES. The area of safe operation, which is used to judge the feasibility of use of a Power MOSFET in an application circuit, is divided into the following 4 areas, each of which is restricted by different conditions. Area [1]: Area restricted by drain current ID, and pulse drain current IDP Area [2]: Area (1) restricted by the maximum power dissipation PD Area [3]: Area (2) restricted by the maximum power dissipation PD (at t=1ms to DC only) Normally, the ASO breakdown tolerance is determined by power dissipation and thermal resistance, and when t=1ms or longer, the breakdown tolerance decreases in high-voltage region due to local current crowding phenomenon. Consequently, a phenomenon similar to secondary breakdown in bipolar transistors occurs. Area [4]: Area restricted by drain-source voltage VDSS (withstand voltage) The ASO chart listed in the data sheet applies to an ideal condition in which the case temperature Tc=25deg. and Duty=0 (Single pulse), and does not exhibit the operation condition of actual switching power supply circuits, etc. Consequently, the chart cannot be used for the review of feasibility of use without making modifications. The chart must be derated according to the actual operating conditions (case temperature Tc, operating frequency f, ON width t, etc.) Safe Operating Area ID=f(VDS):Duty=0(Single pulse),Tc=25 c t= 1s 1 10 Area[1] 10s Area[2] 100s 0 10 Area[3] ID [A] 1ms -1 10 10ms Power loss waveform : Square waveform -2 100ms DC Area[4] 10 PD t -3 10 0 10 1 10 2 10 VDS [V] Fig.3-5 ASO chart of the FMV06N60ES (Condition: Duty=0, Tc=25deg.) Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 13 3 10 Fuji Power MOSFET 3-7. Drain-Source On-state Resistance : RDS(on) Typical Drain-Source on-state Resistance RDS(on)=f(ID):80 s pulse test,Tch=25 C Drain-Source On-state Resistance RDS(on)=f(Tch):ID=3A,VGS=10V 3.5 2.8 VGS=6.0V 6.5V 2.6 3.0 2.4 2.2 RDS(on) [ ] RDS(on) [ ] 2.5 2.0 1.5 max. typ. 1.0 2.0 1.8 7V 8V 10V 20V 1.6 1.4 1.2 0.5 1.0 0.0 0.8 -50 -25 0 25 50 Tch [C] 75 100 125 150 Fig.3-6 ON resistance - channel temperature 0 2 4 6 8 10 12 14 ID [A] Fig.3-7 ON resistance - drain current (standard value) Figure 3-6 is a temperature characteristics chart of ON resistance RDS(on) of the FMV06N60ES. The ON resistance is the most important characteristics for determining the ON dissipation, and is determined by the typ. value and the max. value at the case temperature Tc=25deg. in the characteristics table. The ON resistance has positive temperature characteristics, and in the power dissipation calculation/design in actual operation, the max. value of RDS(on) at the channel temperature Tch=150deg. is read from Fig.3-6 and used as the worst condition. The MOSFET has self-stabilizing function when connected in parallel. When two of more devices are connected in parallel, even if current is fed concentrated on a device having low resistance value due to variation of ON resistance, the device temperature increases due to heat loss, and the resistance value of the device heated due to positive temperature characteristics of the variation of the ON resistance increases, thus decreasing current. Consequently the balance of the current fed through each device is maintained without causing thermal runaway to occur. Figure 3-7 is a ON resistance RDS(on) - drain current ID characteristics chart. The ON resistance depends on drain current and gate-source voltage, and the higher the gate-source voltage, the smaller the ON resistance. We therefore recommend the use under the condition where the gate-source voltage is 10V or higher. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 14 Fuji Power MOSFET 3-8. Capacitance characteristics Ciss, Crss, Coss Figure 3-9 illustrates a simplified equivalent circuit of an N-channel MOSFET. The gate-drain capacitance, namely mirror capacitance, greatly affects the switching characteristics. If the drain-source voltage becomes equal to or smaller than the gate-source voltage, the mirror capacitance surges to approximately 10 times the value of the time when it is larger than the gate-source voltage, as shown in Fig.3-10. D D C (Drain) Cmi(= CGD) CGS RD G VGS= 5V S C GD (C mi ) C DS G (Gate) RG C GS Reverse diode CDS RS 0 S 10 20 30 40 50 VDS [V] (Source) Fig.3-10 Capacitance and drain-source voltage Fig.3-9 Symbols and equivalent circuit of an N-channel MOSFET Typical Capacitance C=f(VDS):VGS=0V,f=1MHz Figure 3-11 is a chart showing the capacitance characteristics of the FMV06N60ES. Each capacitance of the Power MOSFET has the relations shown below: The reverse transfer capacitance of the SuperFAP series is designed to remain small to ensure significantly improved switching characteristics. 3 10 C [pF] Input capacitance: Ciss Cmi CGS Reverse transfer capacitance: Crss Cmi Coss Cmi C DS Output capacitance: 4 10 Ciss 2 10 Coss 1 10 Crss 0 10 -2 10 -1 10 0 10 1 10 2 10 VDS [V] Fig.3-11 Capacitance and drain-source voltage (standard value) Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 15 Fuji Power MOSFET Typical Gate Charge Characteristics VGS=f(Qg):ID=6A,Tch=25 C 3-9. Total Gate Charge : Qg 14 12 Vcc= 120V 300V 480V 10 D.U.T VGS [V] 8 ig 6 4 2 Fig.3-12 Gate charge measurement circuit 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Qg [nC] Fig.3-13 Input gate charge (standard) Figure 3-12 illustrates a gate charge Qg measurement circuit, and Fig. 3-13 illustrates the input gate charge characteristics of the FMV06N60ES. In this measurement, the gate is charged with constant current (ig), and the temporal change of the drain-source voltage (VDS) and gate-source voltage (VGS) is observed. By charging the gate with constant current (ig), the time axis can be read as the quantity of electric charge Qg only by multiplying time by ig. 3-10. Switching characteristics Since the MOSFET is a voltage-controlled device, drive current is not required when ON or OFF state is maintained. Meanwhile, each time switching operation is performed, charging/discharging current of the input capacitance is fed. (1) Resistance load switching characteristics Figure 3-14 illustrates the switching operation waveforms against resistance load. (1-1) Turn ON process Period t0-t1: The MOSFET is driven at time t0. The gate-source voltage increases with the progress of charging of input capacitance Ciss from the internal resistance Ri of the drive circuit. The gate path resistance Rg is compared with Ri and ignored. Period t1-t2: When threshold voltage value is reached at time t2, the MOSFET starts conducting. The drain-source voltage decreases with the increase of the load resistance voltage drop. The drain current increases in the period t1-t2. The mirror capacitance, which is still small at this time, is discharged due to the change in drain-source voltage. The gate-source voltage increases along the transmission characteristics curve. Period t2-t3: At time t2, the drain-source voltage VDS becomes equal to the gate-source voltage VGS. The effect of mirror capacitance that has grown very large appears here. In period t2-t3, the MOSFET operates as a mirror integration circuit. Namely, the gate-source voltage remains the same, whereas the gate charging current is fed via the mirror capacitance to further decrease the drain-source voltage. Period t3-t4: At time t3, the drain-source voltage reaches the final point of the analog area (mirror effect region) of the output characteristics curve. In period t3-t4, the input capacitance Ciss is charged up to the level of the drive voltage. The channel resistance further decreases. At timed t4, the ON resistance RDS(on) (value obtained by dividing the drain-source voltage by the drain current) of the MOSFET reaches the lowest value. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 16 Fuji Power MOSFET (1-2) Turn OFF process Period t5-t6: The turn off process is started by switching the drive voltage to 0 at time t5. The charge accumulated in the input capacitance Ciss, which is at the maximum value at this time, is discharged via the internal resistance Ri of the drive circuit, and the gate-source voltage decreases to the value that allows the drain current to pass through the resistance area of the output characteristics curve. Period t6-t7: When time t6 is reached, the ON resistance increases slightly. The MOSFET operates again as a mirror integrator during the period t6-t7. Namely, the gate drive current is fed via the mirror capacitance, which is still large, with the gate-source voltage maintained at a constant level, and the drain-source voltage increases. Period t7-t8: At time t7, the gate-source voltage becomes equal to the drain-source voltage. The mirror capacitance decreases to a small value. The mirror capacitance, which has decreased, is charged, and the drain-source voltage surges during period t7-t8. The drain current decreases in response to the voltage drop of the load resistance, and the gate-source voltage also decreases. Period t8-t9: The threshold voltage is reached at time t8, and the MOSFET is interrupted completely. Finally, during the period t8-t9, the input capacitance is discharged down to the level of the drive voltage. Since the MOSFET does not have accumulation time, its switching time is determined only by the charging and discharging of the input capacitance. Since the internal resistance Ri of the drive circuit can be selected freely, the switching time of the MOSFET can be adjusted within a wide range. V GS V GS V GS(th) ID V DS ID V DS 0 t1t2t3 t4 t5 t6t7 t8t9 Fig.3-14 Switching characteristics against resistance load (2) Switching characteristics of the induction load with a flywheel diode Assume that in the initial state, the MOSFET is interrupted and current is fed to the induction load and the flywheel diode. (See Fig. 3-15.) (2-1) Turn ON process Period t0-t1: At time t0, the MOSFET is driven via rectangular wave voltage. (See Fig. 3-16.) The gate-source voltage increases with the progress of the charging process of the input capacitance Ciss by the internal resistance Ri of the drive circuit. Period t1-t2: At time t1, the threshold voltage is reached. During period t1-t2, the drain current increases in proportion to the gate-source voltage, whereas the drain-source voltage is maintained at the operation voltage level due to characteristics of the diode. Period t2-t3: At time t2, the transistor carries the entire load current. Since the reverse recovery current of the diode is added to the load current in the subsequent period t2-t3, the drain current further increases. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 17 Fuji Power MOSFET Period t3-t4: At time t3, namely at the polarity reversing point of the reverse recovery current of the diode, the drain current reaches the maximum value. Up to that time, the drain-source voltage remains at the same level as the operating voltage. The gate-source voltage reaches a value capable of conducting the peak current generated in the transistor. In the period t3-t4, the drain-source voltage decreases, and the reverse voltage of the diode increases by the same amount. In normal cases, the drain-source voltage decreases at the same rate as the mirror capacitance is discharged depending on the gate drive voltage, and the gate-source voltage must be maintained at a constant level as in the following period t4-t5 (mirror integrator). However, in the period t3-t4, the change in drain current resulting from the decrease in reverse recovery current of the diode affects the switching process. If the drain current decreases, the gate source capacitance is discharged via the mirror capacitance. The gate-source voltage decreases to the value sufficient to conduct the drain current. Consequently, sharp drain-source voltage waveforms are generated during this period. Due attention should be paid to the process in which a change is caused in the drain-source voltage in the period t3-t4. If the MOSFET is driven at low resistance, the drain current increase rate is high, and the change in commutation current of the flywheel diode also increases. Consequently, high reverse recovery current of the diode is generated, which reaches the maximum value and then decreases suddenly. Note that the sharp change in the reverse recovery current of the diode resulting in dissipation may cause excessive voltage increase within the circuit, thus resulting in an overvoltage breakdown. (2-2) Turn OFF process Period t8-t9: The turn OFF process is started at time t8. At time t9, the gate-source voltage decreases to the value allowing the drain current to pass through the resistance area of the output characteristics curve. Period t9-t10: In the period t9-t10, the transistor operates as a mirror integrator having a large mirror capacitance. Period t10-t11: After the drain-source voltage exceeds the gate-source voltage at time t10, the transistor operates as a mirror integrator having a small mirror capacitance. Period t11-t12: iF The flywheel diode is conducted at time t11, and the drain-source iL voltage is maintained at a constant level. The drain current decreases in proportion to the gate-source voltage. iD Period t12-t13: When the gate-source voltage is decreases to the threshold iL voltage at time t12, the drain-source voltage reaches 0. In the period t12-t13, the input capacitance is discharged to 0. Load current V GS V GS t V GS(th) iF ID V DS Diode current ID t iD V DS 0 t1 t2t3t4 t5t6 t7 t8 t 9 t 10 t 11 MOSFET current t 12 t 13 t Fig.3-15 Current characteristics at the time of induction load switching Fig.3-16 Switching characteristics of induction load with flywheel diode Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 18 Fuji Power MOSFET 4. Circuit design and mechanism of breakdown 4-1. Avalanche breakdown 4-1-1. What is avalanche breakdown? When an inductance load such as transformer is subjected to high-speed switching using a Power MOSFET, excessive surge voltage may be applied, the withstand voltage of the Power MOSFET may be exceeded, and the breakdown area may be entered. The avalanche breakdown is defined as a mode in which due to avalanche operation the channel temperature Tch and avalanche current IAR exceed the absolute maximum Source rating, resulting in breakdown. Al-Si (Source electrode) PSG (Insulation film) (1) Mechanism of avalanche breakdown. Poly-Si (Gate electrode) Figure 4-1 shows the cross-sectional structure of the MOSFET. SiO2 (Oxide film) n+ A bipolar transistor exists parasitically within the MOSFET. If overvoltage is applied to the MOSFET, and the withstand Parastic Rb Bipola Transistor Vzd Vzb voltage of the device is exceeded, avalanche current is fed. The major flows of the avalanche current is as follows: [1] Drain - Rzd - Vzd - Source Rzd Rzb [2] Drain - Rzb - Vzb - Rb - Source First of all, the avalanche current flows by the route of [1] when n[1] [2] the avalanche happens. The avalanche voltage increase by n+ generation of heat because of the avalanche current, and the Metal (Drain electrode) avalanche current begins to flow to the route of [2]. The potential difference is caused by this current in Rb and heat is generated. Drain The resistance of Rb increase by generation of heat, and VBE of Fig.4-1 Cross-sectional structure of a parasitic bipolar transistor decrease. The current that flows in the MOSFET Vzb divides into Rb and VBE when the potential difference in Rb higher than VBE of a parasitic bipolar transistor, and a parasitic bipolar transistor malfunctions. Therefore, the current crowding happens in the part where the avalanche was caused, and MOSFET breakdown. (2) Technology for increasing the resistance to avalanche breakdown Generally, to improve the resistance to avalanche breakdown of the MOSFET, the base Rb of the parasitic bipolar transistor is decreased, and a cell structure not allowing concentration of electric field is adopted. The SuperFAP series adopts the following techniques to increase the avalanche capacity. [1] Adopting a structure where by arranging a simple spherical p diffusion layer carefully, concentration of electric field is loosened to eliminate local concentration of avalanche current [2] Adopting a structure where by arranging a simple spherical p diffusion layer carefully, the entire area of pn diode is increased, and avalanche permissible current per unit area is increased [3] Adopting a structure where by forming a high-concentration p+ diffusion layer inside the channel p diffusion layer, the base resistance Rb of the parasitic bipolar transistor is decreased and the operation of the parasitic bipolar transistor is suppressed (3) Measurement of the avalanche capacity Figure 4-2 illustrates a circuit for measuring the avalanche capacity of the MOSFET, and Fig.4-3 illustrates the measured waveform. If a voltage exceeding VGS(th) is biased to the gate of the MOSFET, drain current ID starts to flow within the MOSFET via an inductance L. At this time, the drain current ID flows within the channel area. If the gate voltage of the MOSFET decreases to VGS(th) or lower, the drain current ID decreases, whereas the drain voltage VDS surges. The drain voltage VDS increases until it reaches the withstand voltage of the device, and is cramped. The residual energy accumulated in the inductance L continues flowing as drain current ID. At this time, since the channel area is interrupted, the drain current flows as avalanche current. The capacity of the MOSFET of consuming the energy accumulated in the inductance L is defined as the avalanche capacity. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 19 Fuji Power MOSFET Fig.4-2 Avalanche capacity measurement circuit Fig.4-3 Avalanche waveform (4) How to guarantee the avalanche capacity The SuperFAP series defines the avalanche capacity using the following items: [1] Avalanche current IAR Permissible current at occurrence of an avalanche. Generally, permissible avalanche current decreases with the increase of temperature, which is why temperature derating is provided in some cases. The SuperFAP series do not provide temperature derating, and guarantee is made in the same temperature range. [2] Avalanche energy EAS The permissible avalanche energy at single pulse at the specified power voltage and under inductance condition. Since it is restricted by channel temperature, the permissible energy varies depending on the operating temperature conditions. (5) Feasibility of use under avalanche condition The following must be satisfied when using the MOSFET for actual avalanche operation: [1] The current value at the time of avalanche is the lower than the guaranteed avalanche current. [2] The channel temperature falls within the guarantee range (normally Tch150deg.). The channel temperature in [2] must be considered even when avalanche operation is not performed. Since power dissipation increases under avalanche operation, more attention should be paid. Figure 4-4 illustrates the waveform at turn OFF in actual avalanche operation. There may be a case in which even if the voltage at turn OFF exceeds the maximum rated withstand voltage VDS, avalanche current may not be fed due to high withstand voltage of the device. In such cases, power dissipation calculation should be made assuming that avalanche is occurring during the period in which the maximum rated withstand voltage VDS of the device is exceeded. BV DSS I D = I AV Actual current waveform V DS Fig.4-4 Typical waveform at avalanche operation Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 20 Fuji Power MOSFET 4-2. ASO breakdown ASO breakdown is classified into overcurrent, overpower, and overvoltage breakdowns. 4-2-1. Overcurrent breakdown Due to short circuit of loads, etc., current exceeding the area restricted by the drain current ID and pulsed drain current IDP in ASO is fed, causing the device to heat up and resulting in breakdown or melting of the internal wiring of the package, which is defined as overcurrent breakdown. 4-2-2. Overpower breakdown If the drain current ID and the drain-source voltage VDS are simultaneously applied, power dissipation exceeding the area restricted by the maximum power dissipation PD in ASO is generated, thus causing the device to heat up excessively, which is defined as overpower breakdown. 4-2-3. Overvoltage breakdown If a large surge voltage exceeding the area restricted by the drain-source voltage VDSS (withstand voltage) in ASO is applied due to high-speed switching of an inductance load such as transformer, and thus the breakdown area is entered, the device is heated abnormally, resulting in breakdown or avalanche breakdown, which is defined as overvoltage breakdown. 4-3. Diode breakdown 4-3-1. What is diode breakdown? In a bridging circuit using a drain-source parasitic diode, sharp change in voltage (dv/dt) and/or current (di/dt) during reverse recovery operation of the parasitic diode causes the parasitic bipolar transistor of the MOSFET to arc and large current to be fed, thus resulting in uncontrollable state and breakdown, which is defined as diode breakdown. 4-3-2. Mechanism of diode breakdown Source If voltage is applied in reverse direction in a state in which Al-Si (Source electrode) current is fed to the parasitic diode (voltage is applied between PSG (Insulation film) Poly-Si (Gate electrode) D and S), the parasitic diode performs reverse recovery operation. A part of this recovery current is fed through the Rb of the parasitic SiO2 (Oxide film) n+ bipolar transistor via route [2] in Fig.4-5 as in the case of an Parastic Rb avalanche. In this case, the charging current to the parasitic Bipola Transistor Vzd Vzb capacitance Cds (=Cvzd+Cvzb) via the recovery dv/dt is also fed to the Rb of the parasitic bipolar transistor. Due to the composite effect of these two currents, potential difference is Rzd Rzb generated in the Rb, and consequently parasitic bipolar transistor n(between B and E) is biased. When current starts to flow from the [1] [2] drain through the parasitic bipolar transistor to the source, the n+ Metal (Drain electrode) temperature of the parasitic bipolar transistor increases, causing the resistance value of the Rb to increase and parasitic bipolar Drain transistor threshold voltage VEB to decrease, which further causes the parasitic bipolar transistor to be biased, current is concentrated, Fig.4-5 Current route thus resulting in a breakdown of the MOSFET. To prevent this from at avalanche breakdown occurring, restrictions are imposed on the recovery di/dt affecting the recovery current and the recovery dv/dt affecting the charging current. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 21 Fuji Power MOSFET 4-4. Breakdown due to parasitic oscillation As a result of directly connecting gate terminals (without inserting gate resistance Rg in between) when connecting devices in parallel, or sudden change in the drain-source voltage or current at the time of turn ON/OFF, parasitic oscillation occurs at the gate. Due to this parasitic oscillation, the gate-source voltage VGS may exceed the rated voltage VGS, or the device may malfunction due to the parasitic oscillation of the gate, thus resulting in thermal breakdown, which is called a breakdown due to parasitic oscillation. The gate breakdown that occurs due to static electricity or parasitic oscillation is in two modes: One is thorough breakdown, namely short circuit between the gate and the source or between the drain and the source [1], and the other is halfway operation in which the impedance between the gate and the source decreases whereas the leakage current between the drain and the source increases [2]. Under normal operating conditions, the trace of breakdown increases due to short circuit between the drain and the source in mode [1], and in mode [2] the operation by voltage whose VGS is lower than prescribed causes malfunction to occur and leakage current to increase, thus resulting in ASO breakdown. It is therefore difficult to judge the occurrence of gate breakdown from the trace of the breakdown. Figure 4-6 shows parasitic oscillation waveform when the gates of the MOSFET are directly connected in parallel. This oscillation occurs when the drive voltage reaches the threshold voltage of the MOSFET and the drain current starts to flow. Top: Each gate is connected directly. Center: A 10 resistance is connected to each gate in series. Bottom: A ferrite bead is connected to each gate in series. Fig.4-6 Change in gate-source voltage at parallel switching This oscillation occurs because of extremely high forward transconductance of the MOSFET. The resonance circuit consists of an external circuit, inductance of each MOSFET itself, and the parasitic capacitance. The voltage generated due to this oscillation exceeds the maximum gate-source voltage value in many cases, thus breaking the device. It is therefore recommended to connect a resistance of 4.7 or higher to each gate of the MOSFET connected in parallel. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 22 Fuji Power MOSFET 4-5. Electrostatic breakdown 4-5-1. What is electrostatic breakdown? If static electricity or surge voltage is applied to the gate terminal of the MOSFET through human body or experimental devices, the resistance to static electricity at the gate terminal is exceeded, thus resulting in a breakdown, which is defined as electrostatic breakdown. 4-5-2. Prevention of electrostatic breakdown of the Power MOSFET (measures) Compared with small-signal MOSFET and MOS IC, the Power MOSFET has significantly higher oxide film resistance. However, since damage may occur due to static electricity as in the case of these MOS products, pay special attention when handling the Power MOSFET. TESTER electrically conductive mats wrist strap electrically conductive floor GND Fig.4-7 Example of measures against GND breakdown by static electricity (1) How to discharge static electricity from an electrostatic body When making a workbench protected against static electricity, proper use of an electrically conductive table mat, wrist strap, and floor mat allows static electricity built up to be removed. The speed of removing the charge is determined based on the resistance on the capacitance route of the conductive body. Figure 4-8 shows an equivalent circuit in which the conductive body has capacitance C and the route resistance of R. t=0 Initial Voltage V0 Capacitance of conductive body C Route Resistance R Fig.4-8 Equivalent circuit for static electricity discharge The voltage of the conductive body is expressed by the following formula as the function of time t: t V V0 exp RC V = Voltage [V] of the charged body at time t V0 = Initial voltage [V] of the charged body t = Second C = Capacitance [F] of the charged body R = Route resistance [] Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 23 Fuji Power MOSFET <Example> Assume that the static electricity level of a worker is decreased to 100V or lower within one second according to technical material TB57-1 of the Electric Industries Association of Japan (EIAJ). Substitute the following into the above formula: V = 100V (safe voltage) V0 = 10kV (Initial voltage of the human body or charged body) t = 1sec. (Longest permissible time for achieving the safe voltage of 100V) C = 200pF (Average of human capacitance 100pF to 400pF) R = Maximum permissible resistance [] to the ground 1 100 1 10 4exp 2 200 10 R 9 R 1.09 10 = 1090 M can thus be obtained. From this calculation, it is found that if the resistance from the table mat, floor mat, or 9 wrist strap to the ground is 10 or lower, discharge to obtain safe voltage, 100V, can be performed within one second, and the parts can thus be protected against electrostatic breakdown. - About the breakdown value of a device due to electrostatic discharge Table 4-1 lists the voltage range in which various devices may result in breakdown due to electrostatic discharge from workers. Table 4-1 Breakdown voltage by device Type MOSFET Junction FET C MOS Voltage range [V] 100 ~ 200 140 ~ 10000 250 ~ 2000 Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 24 Fuji Power MOSFET 5. Thermal design 5-1. Concept of heat dissipation (1) Transient thermal impedance and steady thermal resistance The heat dissipation treatment of power dissipation that occurs at the channel of a Power MOSFET is performed by mounting the MOSFET to a cooling body, or by the device itself. Figure 5-1 simulates the heat radiation route in the former case in an electrically equivalent circuit. MOSFET Chip Metal base PD R2 R1 ch C1 Insulation sheet R3 R4 C2 PD Cooling body C3 R5 C4 Power dissipation MOSFET chip, soldered layer PCD1 ,R 1 CC12,R ,R12 MOSFET Metal base CR23,R 2 Contact thermal resistance R3 C 3 ,R 4 Insulation sheet C 3 ,R 4 (including a part of contact thermal resistance) C 4 ,R 5 C 4 ,R 5 Cooling body Fig.5-1 Electric equivalent circuit showing thermal behavior In the equivalent circuit in Fig.5-1, the transient thermal impedance is the thermal resistance within the time range affected by the thermal capacitances C1 to 4, and is the function of time. As the transient thermal impedance characteristics of each device, the maximum value is displayed on the data sheet, which is equivalent to D 0. The transient thermal impedance of the cooling body is found by the following formula: t f Rf (t ) R f a 1 where, f R f aVC Rf-a : Cooling body steady thermal resistance [deg./W] t : Time [S] f : Thermal time constant of the cooling body [S] V : Cooling volume [cm3] : Specific gravity [g/cm3] C : Specific heat [W* S/g* deg.] Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 25 Fuji Power MOSFET Table 5-1 lists the specific gravity of materials required for this calculation, and Fig.5-2 illustrates the steady thermal resistance of an aluminum cooling plate (coated in black). Thermal resistance of an aluminum plate Material Specific Specific heat gravity [W* S/g* deg.] Thermal resistance (deg./W) Table 5-1 Specific gravity and specific heat of each material 3 [g/cm ] Aluminum 2.71 0.895 Copper 8.96 0.383 2 Area of a radiator plate (cm ) Fig.5-2 Steady thermal resistance of the aluminum cooling plate Meanwhile, since the steady thermal resistance is not affected by thermal capacitance at all, the channel temperature can be found easily. PD Tch Ta Rch c Rc i Ri Ri f Rf a Tch : Channel temperature Ta : Ambient temperature Rch-c : Thermal resistance between channel and case (MOSFET thermal resistance) Ri : Insulation sheet Rc-i, Ri-f : Contact thermal resistance Rf-a : Thermal resistance of cooling body PD : Generated power dissipation 5-2. Transient thermal impedance characteristics of the device The specification of the MOSFET lists the transient thermal impedance characteristics of the device to assist thermal designing. Figure 5-3 illustrates the transient thermal impedance characteristics of the FMV06N60ES. For example, assume a single pulse having pulse width of 1 ms, and the permissible power dissipation PD in the case in which the device is mounted to a cooling body of 5deg./W under Ta=40deg. condition can be calculated by using the following formula: Tchmax Ta Rthf a Rth1 ms 1 10 150 40 5 / W 0.15 / W 21.4 [W] 0 10 Zth(ch-c) [C/W] PD Maximum Transient Thermal Impedance Zth(ch-c)=f(t):D=0 -1 10 -2 10 Fig.5-3 Transient thermal impedance characteristics of the FMV06N60ES -3 10 -6 -5 10 10 -3 10 t [sec] Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 -4 10 26 -2 10 -1 10 0 10 Fuji Power MOSFET 5-2. Calculation of channel temperature When using a MOSFET, it is essential that the channel temperature fall within the maximum rating under the operating condition. It is therefore necessary to find the channel temperature based on the operating waveforms, thus verifying whether the MOSFET can be used or not. (1) Calculation of channel temperature for rectangular wave power dissipation Table 5-2 lists the channel temperature calculation formulae for continuous load, single pulse load, continuous pulse load, and irregular pulse load following the continuous pulse load. Table 5-2. Channel temperature calculation formula Load Continuous load Channel temperature calculation formula Tch Tch Ta PRthch a P 0 Single pulse load Tch Ta PRth(t1) Tch P 0 t1 Continuous pulse load t t Tch Ta P 1 Rthch a 1 1 t2 t2 Tch P Rtht1 t 2 Rtht 2 Rtht1 t1 t2 Irregular pulse load following continuous pulse load P3 P2 P1 Tch t t Tch Ta P1 1 Rthch a 1 1 t2 t2 Rtht1 t 2 Rtht 2 P2Rtht6 t3 Rtht6 t 4 t1 t2 t3 t4 t5 t6 P3Rtht6 t5 Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 27 Fuji Power MOSFET (2) Calculation of channel temperature for complicated power dissipation waveforms If the MOSFET has a complicated power dissipation waveform, the channel temperature can be calculated by converting the waveform into a rectangular wave as shown in the dotted line in Fig.5-4, and based on the (a) Power dissipation waveform concept of superposition. Po Po Po Po Po Po Po Po Po t T (b) Power dissipation approximation (averaging) PAV (c) Application of concept of superposition (power dissipation) PAV -PAV -Po (d) Application of concept of superposition (temperature increase) Tch(peak) Tch(AV) Fig.5-4 Channel temperature in complicated power dissipation waveforms (3) Specific channel temperature calculation To calculate the channel temperature of the MOSFET, the following are required: (a) Waveform for one cycle (VDS, ID, and cycle T must be clear.) (b) Expansion of turn ON/OFF waveform (c) Operating condition (case temperature Tc, etc.) The steps for calculating channel temperature are shown below. [1] Obtaining operation waveform En t ir e wave fo r m (T h e c yc le m u st be c le ar . ) VDS ON period OFF period ID En lar ge d wave fo r m at t u r n ON VDS En lar ge d wave fo r m at t u r n OFF 50~100ns/div 50~100ns/div ID ID VDS * If turn ON dissipation and turn OFF dissipation can be ignored, the waveform need not be obtained. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 28 Fuji Power MOSFET [2] Approximation of operation waveform Operation waveform at turn ON Power dissipation is calculated by the following formula: VDS V 0 I ID I0 V I0 I t V0 V t PS t I 0 t V0 dt t t 0 Appr o xim at e d dissipat io n P Pt-on PS t If the power dissipation for the turn ON period is calculated using the above formula, the result of the calculation "P" is expressed as "Pt-on." Pon Turn ON dissipation: Turn OFF dissipation: Pt-on Pt-off ON dissipation: Average power Pon dissipation at ON: Pav(on) Average power dissipation: Pav Pav Pav ( on ) Pav ( on ) t 3 1 T Pt on t1 Pon t 2 Pt off t3 T t * If the turn ON dissipation and turn OFF dissipation can be ignored, they need not be taken into consideration. Example: In the case of pulse width of (Ta) Rth( ch c )(Ta ) Rth( ch c )(1ms ) Ta 0.001 Rth(ch-c)(1ms) : Duty=0, Transient thermal impedance value at 1ms 1 10 0 10 Zth(ch-c) [C/W] [3] Calculation of transient thermal impedance The transient thermal impedance value at each time can be read from the transient thermal impedance chart in Fig.5-5. Note, however, that if the pulse width is 1 ms or shorter, the value can be found by using the following formula: Maximum Transient Thermal Impedance Zth(ch-c)=f(t):D=0 -1 10 -2 10 -3 10 -6 10 -5 10 -4 10 -3 10 -2 10 -1 10 t [sec] Fig.5-5 Transient thermal impedance chart Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 29 0 10 Fuji Power MOSFET [4] Calculation of channel temperature Pt-off Power dissipation approximation model Pav Pt-on Pav(on) Pon Temperature increase model Channel temperature increase calculation formula : Tch c Pav Rth( ch c ) Pav ( on ) Pav Rth(T t ) Pav ( on ) Rth(T ) Pt on Rth(t ) Pon Pt on Rth(t 2t 3) Pt off Pon Rth( t 3) * If turn ON dissipation and turn OFF dissipation can be ignored, they need not be taken into consideration. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 30 Fuji Power MOSFET 6. Cautions in mounting and handling To ensure safe operation over a long period of time, follow the precautions on handling shown below. (1) Soldering When a semiconductor device is soldered, the temperature of the lead exceeds the maximum rated storage temperature. Since quality assurance regarding the resistance against soldering is applicable to the level shown below, perform soldering within the listed range. (a) Recommended mounting condition Methods Categories Through-Hole Surface Mount Packages Wave Soldering Wave Soldering (Full dipping) (Only terminal) TO-3PL Unable TO-3P Unable TO-247 TO-3PF Soldering iron Infrared Reflow Air Reflow Possible Unable Unable Limited to 1time Possible Unable Unable Limited to 1time Unable Possible Unable Unable Limited to 1time Unable Possible Unable Unable Limited to 1time (Re-work) TO-220 Unable Possible Unable Unable Limited to 1time TO-220F Unable Possible Unable Unable Limited to 1time T-Pack(L) Unable Possible Unable Unable Limited to 1time K-Pack(L) Unable Possible Unable Unable 1time T-Pack(S) Unable Unable Possible Possible Unable T-Pack(SJ) Unable Unable Possible Possible Unable K-Pack(S) Unable Unable Possible Possible Unable TFP Unable Unable Possible Possible Unable - Through-Hole Package Soldering temp. 2605 deg. 35010 deg. Immersion time 101 sec 3.50.5 sec - Surface Mount Package Number of times(Reflow) Soldering Temp. & Time Package surface Peak Temp. & Time Twice 230 deg., 50sec 260 deg., 10sec (b) The immersion depth of the lead should be up to 1 to 1.5 mm from the device main unit. (c) Be careful not to let the device main unit be immersed in soldering liquid when mounting the device by the solder flow method. (d) When using a flux, it is desirable to use rosin series flux, and not chlorine series flux. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 31 Fuji Power MOSFET (e) Recommended reflow Fig.6-1 Recommended reflow profile (through hole/Pb-free solder specification) Post Cooling Pre-heat Fig.6-2 Recommended reflow profile (SMD/Pb-free solder specification) Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 32 Fuji Power MOSFET (2) Processing and mounting of through hole terminal Handling of lead wire of resin-sealed power transistor (a) Stress to the lead wire If stress of more than necessary is applied to the electrode lead of a semiconductor device, the internal chips and external package may be damaged. To prevent this from occurring, keep the load applied in the direction shown in Fig.6-3 to 1kg or lower. 1kg or lower 1kg Fig.6-3 Stress to the lead wire (b) Caution in molding a lead If there is no other choice but to mold a lead for convenience of parts layout, pay attention to the following: 4mm or more 4mm thin portion 4mm 4mm or more 30 within 30 Fig.6-4 Cautions in molding a lead *Provide an exclusive jig that does not allow stress shown in Fig.6-4 to be applied. *When bending the lead in the horizontal direction, bend it at the thin portion or at the part 4 mm or more away from the transistor main unit, and keep the bending angle within 30. *When bending the lead at the right angle against the type displaying surface, bend it at the portion 4 mm or more away from the transistor main unit. *Molding should be performed only once at a place, and do not perform re-molding or restore the original shape. (c) Insertion into the printed board When inserting a lead to the printed board, coincide the interval of lead wires and that of insertion holes to prevent excessive stress from being applied to the root portion of the leads. To prevent the lead soldered to the printed board from being forcibly bent to mount it to a radiator plate, perform mounting work first and then perform soldering. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 33 Fuji Power MOSFET (3) Washing (Common to through hole and SMD) When soldering is performed using a flux, washing with solvent is required in general. In this case, pay attention to the following: (a) Solvent *Do not use flammable, toxic, or corrosive solvents. *Never use a trichloroethylene series solvent because it contains chlorine. (b) Washing method It is desirable to perform washing by immersing the portion to be washed. If ultrasonic washing is to be performed, set the frequency, avoiding the resonance point (several tens of kHz), and pay attention not to let the device or printed board to directly contact the oscillation source. (4) Mounting to a radiator plate (a) If the fastening torque of the screw for mounting is too low, the thermal resistance increases. On the contrary, if it is too high, the device may be deformed, thus resulting in a failure. Consequently, it is recommended to fasten the screws at the torque listed in Table 6-1. Table 6-1. Semiconductor device fastening torque Package Diameter of mounting hole Screws used Optimum fastening torque (N*cm) TO-220AB 3.6 M3 30-50 TO-220F 3.2 M3 30-50 TO-3P 3.2 M3 40-60 TO-247 3.2 M3 40-60 TO-3PF 3.2 M3 40-60 TO-3PL 3.2 M3 60-80 (b) It is recommended to apply a compound thinly and uniformly to improve the thermal conductivity between the semiconductor device main unit and the radiation plate, thus improving heat dissipation effect. (c) Application of thermal compound As a method for allowing a thermal compound to exist between the device and a cooling body, a compound is applied uniformly to the device, which is then mounted to the cooling body. However, in the case of small products such as the TO220 package, the application work is cumbersome. As a method for filling the gap between the device and the cooling body with a compound, apply an appropriate amount of compound to the case immediately below the semiconductor device chip-mounting portion in a shape of a point, and fasten the device to the cooling body with screws, and the compound expands, filling the gap, and a compound layer containing few air bubbles can thus be formed easily. Compound <Small package such as TO3P> (d) When fastening one device with screws at 2 positions, pay special attention to fasten the screws uniformly. (e) Surface flatness 30 m (f) Surface roughness 10 m (g) Do not taper threaded holes. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 34 Fuji Power MOSFET (5) Cautions in storage and transportation (a) Storage (i) It is desirable that semiconductor devices be stored in a place of normal temperature and humidity. Avoid storing the devices in a place of temperature and humidity far away from the normal values, which are approximately 5 to 35deg. and 45 to 75% respectively. When storing molded type power transistors in an area that becomes extremely dry in winter, humidification by a humidifier is required. If tap water is used for humidification, chlorine contained in it may cause corrosion of the leads of the device. To prevent this from occurring, use pure water or boiled water for humidification. (ii) Avoid storing semiconductor devices in a place where corrosive gas is generated or subjected to much dust. (iii) Avoid storing semiconductor devices in a place subjected to sharp temperature change. Otherwise condensation may occur to the devices. Store the devices in a place having minimum temperature change. (iv) Pay attention not to apply load to semiconductor devices during storage. In particular, if they are stored, stacked on top of each other, unexpected load may be applied. (v) Store the semiconductor devices with each terminal kept unprocessed to avoid occurrence of corrosion, which may result in insufficient soldering at the time of processing. (vi) Contain the devices in a container that does not take static electricity easily, or the one used for the delivery of the product. (vii) All the shelves for storage should be made of a metal. Be sure to ground them. (b) Transportation (i) Be careful not to have impact on the devices by dropping them, etc. (ii) When transporting large number of devices in boxes, place the devices by inserting a soft spacer to prevent the contact electrode surface, etc. from being damaged. (iii) When transporting Fuji Power MOSFET, take measures against static electricity using a conductive bag or aluminum foil to prevent static electricity to build up between the gate and the source. Fig.6-5 Conductive bag (left) and conductive foam (right) (c) Work environment (i) The person who handles the Power MOSFET should use a body earth. As a body earth, wear a wrist strap, copper ring, etc., mount a resistance of approximately 1M, and ground it to prevent electric shock. (ii) Spread a conductive floor mat, tablemat, etc. in a place for handling the Power MOSFET, and be sure to perform grounding. (iii) When using a measuring device such as curve tracer, also ground the measuring device. (iv) Before performing soldering, ground the soldering bath to prevent the leak voltage from the soldering iron or bath from being applied to the Power MOSFET. Be sure to follow the cautions described above to prevent an electrostatic breakdown of the device. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 35 Fuji Power MOSFET 7. Application to switching power supply 7-1. Advantages of Power MOSFET Advantage Feature Powercontrolled For users * Small drive power * Simple drive circuit *Saved energy and improved *High drive voltage * Difficulty in applying to low-voltage driving efficiency *Lower number of parts *High switching speed *Excellent radiofrequency characteristics *High resistance to carrier For users *Compact and reduced cost devaice Majority Disadvantage *Resistant to thermal device * Large power dissipation in allowed of high-voltage devices low-frequency application (high-accuracy control etc.) than that of bipolar (A large radiator plate is transistors required.) *Downsizing of peripheral *Consideration required for *Increased ON devices resulting from breakdown runaway *Larger ON resistance *Higher device performance higher frequency resistance resulting (transformer, capacitance) from temperature *Saved energy and improved heat dissipation design increase efficiency *Improved device reliability *Facilitated heat dissipation design Major advantages of the MOSFET include not only high switching speed but also excellent radiofrequency characteristics and independence of switching time of the temperature. By achieving higher frequency of the switching frequency using these advantages, downsizing of radiofrequency transformers and the LC on the secondary side is allowed. In addition, with the increase of operation frequency, the switching loss (OFF dissipation in particular) becomes dominant, and the effect of the defect of large ON resistance decreases, which is an essential point for selecting devices. Other features are summarized in the following table: Item Area of safe operation Feature Advantage in application *Independent of gate reverse bias voltage *No need of considering reverse bias ASO *Low drive power *No consideration is needed in designing a drive circuit (ASO) Voltage-controlled type *Simple drive circuit when a large load current range is required for the power supply as in the case of pulse load such as motors Positive ON resistance *Easy parallel connection temperature characteristics 7-2. Points to keep in mind when designing a gate drive circuit (1) Drive circuit (a) The drive power dissipation is calculated from Ciss based on the gate charge amount Qg. Generally, in designing a Power MOSFET drive circuit, the drive power dissipation can be found using the following formula: Drive power dissipation: Pd f Ciss VGS 2 where, f : Operation frequency VGS : Gate-source voltage t : Switching time Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 36 Fuji Power MOSFET The input capacitance Ciss in this formula in the data sheet is the value obtained with VDS fixed, and the value obtained by substituting this value into the formula deviates from the actual power dissipation. The reason for this is that a gate-drain capacitance CGD, which is a mirror capacitance, exists in the Ciss, CGD is the function of the drain-source voltage VDS, and the gate-source capacitance CGS is the function of VGS. If the Ciss in the above formula is regarded as the function of VDS and VGS in actual designing of a drive circuit, the calculation becomes extremely complicated and cumbersome. Therefore, specifying the gate charge amount Qg as the function of VGS and VDS is the optimum method. Figure 7-1 illustrates the input charge of the FMV06N60ES (600 V/6 A). Typical Gate Charge Characteristics VGS=f(Qg):ID=6A,Tch=25 C 14 12 Vcc= 120V 300V 480V 10 VGS [V] 8 6 4 2 0 0 5 10 15 20 25 30 35 40 45 50 55 60 Qg [nC] Fig.7-1 Typical Input Charge The drive power dissipation of the drive circuit can be found based on the gate charge Qg, using the following formula. Drive power dissipation: Pd f Qg VGS (Example) When driven at VGS = 10 V and f = 200 kHz *When the drive power dissipation is calculated using the Ciss defined in the specification: Ciss=2280 , Pd=0.05W *When the drive power dissipation is calculated using the gate charge Qg: Qg=54nC , Pd=0.11W The drive power dissipation calculated using Qg is approximately twice as large as the drive power dissipation calculated using the Ciss defined in the specification. (b) Other points Item Switching loss Drive circuit voltage Caution *To decrease the switching loss, measures should be taken to discharge the gate charge in a short time. *The voltage should be maintained at least 8V or higher. To achieve this, measures such as stopping the oscillation before VGS decreases to 8V or lower should be taken. *Measures should be taken not to allow VGS to exceed the gate threshold voltage VGS(th) at the time of turning OFF. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 37 Fuji Power MOSFET <Typical drive circuit> Direct drive ON pulse Q1 Q1 E E OFF pulse Q2 Q2 Pulse trans drive Q1 T E C R Q2 T Q2 E Q1 1.000 Standardized efficiency Rg=10ohm1) (Rg=10ohm regarded as 1) (2) SuperFAP series and gate resistance Rg Compared with conventional products, high-speed switching is allowed with the SuperFAP series by reduced the gate charge. Conventionally, the gate resistance was decreased to increase the speed, thus decreasing the switching loss. Meanwhile, with the SuperFAP series, high-speed switching is allowed with a larger gate resistance than that of the conventional one, and the switching loss can be reduced. Figure 7-2, 7-3, and 7-4 are the charts illustrating the turn OFF dissipation, temperature increase, and power efficiency obtained with the conventional product and the SuperFAP series mounted to the MOSFET for main switching of AC adaptor for 90W worldwide input laptop PCs. 0.995 0.990 0.985 0.980 0.975 2SK3502 2SK3502 Conventional product 0.970 10 Standardized temperature increse T T(Rg=10ohm1 (Rg=10ohm regarded as 1) Standardized Poff Poff Rg=10ohm (Rg=10ohm regarded as1 1) 3 2 50 60 70 Rg (ohm) 1.6 70 2SK3502 2SK3502 Conventional product 1.5 1.4 1.3 1.2 1.1 1.0 10 20 30 40 50 Rg (ohm) Fig.7-3 Gate resistance and standardized 60 Fig.7-4 Gate resistance and standardized turn OFF dissipation temperature increase Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 60 1.7 4 40 50 power efficiency 5 30 40 Fig.7-2 Gate resistance and standardized 2SK3502 2SK3502 Conventional product 20 30 Rg (ohm) 6 1 10 20 38 70 Fuji Power MOSFET 7-3. Cautions for parallel connection To increase the output capacitance of electronic devices, power devices to be used for the main circuit of the electronic device are connected in parallel in many cases. Generally, the Power MOSFET is easier to be connected in parallel than bipolar transistors. The reason for this is that the operation resistance of the Power MOSFET has a positive temperature coefficient, and that even if unbalance should occur between the current fed through each device connected in series, the positive temperature coefficient offsets the current unbalance. However, if the wiring connecting each MOSFET in parallel is unbalanced, unbalance in current occurs during the transient period of the ON and OFF switching operation, thus resulting in non uniform channel temperature. Cautions in connecting the Power MOSFET in parallel are described below. (1) Gate parasitic oscillation If the gate of the MOSFET is directly connected in parallel, parasitic oscillation may occur to the gate and thus resulting in the breakdown of the device. (See 4-4. Breakdown due to parasitic oscillation) To prevent this from occurring, connect a resistance of 4.7 or higher to each gate of the MOSFET connected in parallel. (2) Circuit wiring It is desirable that the gate drive and main circuit wiring connecting two or more MOSFETs in parallel be uniform. In particular, the counter electromotive force, Vls = ls*di/dt , generated due to the inductance Is contained in the wiring between the main circuit and the source electrode affects the voltage close to the gate-source electrodes of the MOSFET, thus having a large impact on the current balance at the time of turning ON and OFF of the MOSFET. l G1 R g1 l G2 R g2 l D1 l D2 l S1 l S2 Fig.7-6 Wiring inductance equivalent circuit Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 39 Fuji Power MOSFET Figures 7-7 and 7-8 illustrate the current balance waveforms at the time of turn ON and OFF generated due to the difference between the drain and the source wiring inductance ID and IS of the main circuit (two SuperFAP-Gs rated at 500 V/10 A are used). Turn ON current balance Turn OFF current balance Ld=6nH Ld=45nH Fig.7-7 When there is a difference in the inductance of the drain electrode wiring of the main circuit Turn ON current balance Turn OFF current balance Ls=2nH Ls=6nH Ls=21nH Fig.7-8 When there is a difference in the inductance of the source electrode wiring of the main circuit Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 40 Fuji Power MOSFET As shown above, the current balance at the time of turn ON in parallel operation depends largely on the wiring of the source of the main circuit. Consequently, the wiring between the source and the ground should be kept as short and thick as possible to minimize the inductance. (3) Improving the current unbalance (a) Characteristics of the MOSFET and current balance The positive temperature coefficient of the operation resistance of the MOSFET affects the current unbalance generated in parallel operation to be improved at all times. However, if the MOSFET is used at radiofrequency as in the case of an application to a switching power supply, the unbalance in power dissipation, which may be generated due to the unbalance in transient current at turn ON and OFF, cannot be ignored. As the method for improving this current unbalance, Fuji Power MOSFETs classified into various standard threshold voltage VGS(th) classes are available. Table 7-1 Standard VGS(th) classification of the SuperFAP series Series SuperFAP series SuperFAP series (logic series) (nonlogic series) Range Range C 0.95 V ~ 1.30 V - D 1.25 V ~ 1.60 V - E 1.55 V ~ 1.90 V - F 1.85 V ~ 2.20 V - G 2.15 V ~ 2.50 V - L - 2.95 V ~ 3.35 V Rank symbol M - 3.30 V ~ 3.70 V N - 3.65 V ~ 4.05 V P - 4.00 V ~ 4.40 V R - 4.35 V ~ 4.75 V S - 4.70 V ~ 5.00 V Note: Ranks cannot be specified. (b) Drive condition and current balance As a method for improving the current unbalance at turn OFF, in particular, measures should be taken to keep the switching time as short as possible. Figure 7-9 illustrates the current unbalance at turn ON and turn OFF due to increase/decrease of gate series resistance (500V/10A MOSFET is used). Turn ON current balance Turn OFF current balance Rg=10 Rg=200 Fig.7-9 Current balance waveform due to the difference in series gate resistance Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 41 Fuji Power MOSFET 7-4. Example of applications Application MOSFET :Planer / :SJ-MOS Breakdown MOSFET On-state Resistance RDS(on) [ohm] Recommended Voltage Power range [W] IC Circuit type BVDSS [V] CRM-PFC CCM-PFC Standard Single Power Supply Forward ~30 50 100 150 200 300 0.85 0.52 0.52 0.38 0.27 500 1k 2k 600V FA5590series FA5502 0.19 0.19x2 0.11x2 FA5610series 600V FA5504/10/14 2.5 2.0 1.4 1.0 1.4x2 1.0x2 FA5604 900V Double 0.27 0.19 500V - Forward Phase-shift 0.38 0.19 600V - Full-Bridge CRM-PFC 500V / FA5590series CCM-PFC 600V 0.52 0.38 0.31 0.19 0.19x2 FA5610series Current Resonant 500V 1.5 0.85 0.52 0.38 LCD-TV M-Power PDP-TV QR 2.0 1.5 FA5571series 800V Boost- 600V Photovoltaic - Chopper 0.05x2 Power Conditioner Full-Bridge 500V 0.05x2 100V / 600V Adapter Ringing 110V (Low Power) choke 200V / 2.3 900V 220V CCM-PFC Desktop PC / Single PC server Forward 4.6 FA5502 0.4 0.4 0.19 0.19x2 0.19x2 FA5504/10/14 2.0 1.4 1.0 FA5604 600V FA5610series 900V Double 0.52 0.27 0.19 500V - Forward CRM-PFC Adapter / 0.52 0.38 FA5528series 2.3 1.2 0.75 0.38 FA5592series 600V IJP / LBP Flybuck-QR FA5590series Note PC- Flybuck-PWM 600V 2.3 1.2 0.75 0.38 170m 66m 66m 66mx2 66mx2 66mx2 600V Single FA5571series 200V Bus Forward converter Phase-shift - 10mx8 10mx8 100V - Full-Bridge * The values in the above table are guidelines. Select your MOSFET after due consideration. Fuji Electric Co., Ltd. AN-080E Rev.1.0 Apr-2011 42