Product Folder Sample & Buy Support & Community Tools & Software Technical Documents LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 LM5002 Wide Input Voltage Switch Mode Regulator 1 Features 3 Description * * The LM5002 high voltage switch mode regulator features all of the functions necessary to implement efficient high voltage boost, flyback, SEPIC and forward converters, using few external components. This easy to use regulator integrates a 75-V N-Channel MOSFET with a 0.5-A peak current limit. Current mode control provides inherently simple loop compensation and line-voltage feed-forward for superior rejection of input transients. The switching frequency is set with a single resistor and is programmable up to 1.5 MHz. The oscillator can also be synchronized to an external clock. Additional protection features include: current limit, thermal shutdown, undervoltage lockout and remote shutdown capability. The device is available in both 8-pin SOIC and 8-pin WSON packages. To create a custom regulator design, use the LM5005 with WEBENCH(R) Power Designer. 1 * * * * * * * * * * * * * * Integrated 75-V N-Channel MOSFET Ultra-Wide Input Voltage Range from 3.1 V to 75 V Integrated High Voltage Bias Regulator Adjustable Output Voltage 1.5% Output Voltage Accuracy Current Mode Control with Selectable Compensation Wide Bandwidth Error Amplifier Integrated Current Sensing and Limiting Integrated Slope Compensation 85% Maximum Duty Cycle Limit Single Resistor Oscillator Programming Oscillator Synchronization Capability Enable and Undervoltage Lockout (UVLO) Pin 8-Pin SOIC Package 8-Pin WSON Package Thermal Shutdown With Hysteresis Device Information(1) PART NUMBER LM5002 2 Appliwcations * * PACKAGE BODY SIZE (NOM) SOIC (8) 4.90 mm x 3.90 mm WSON (8) 4.00 mm x 4.00 mm (1) For all available packages, see the orderable addendum at the end of the data sheet. DC-DC Power Supplies for Industrial, Communications, and Automotive Applications Boost, Flyback, SEPIC, and Forward Converter Topologies Typical Application Circuit + 12 V to + 36 V + 48 V VIN EN VCC SW COMP LM5002 RT GND FB Copyright (c) 2016, Texas Instruments Incorporated 1 An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications, intellectual property matters and other important disclaimers. PRODUCTION DATA. LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com Table of Contents 1 2 3 4 5 6 7 Features .................................................................. Appliwcations......................................................... Description ............................................................. Revision History..................................................... Pin Configuration and Functions ......................... Specifications......................................................... 1 1 1 2 3 4 6.1 6.2 6.3 6.4 6.5 6.6 4 4 4 4 5 6 Absolute Maximum Ratings ...................................... ESD Ratings.............................................................. Recommended Operating Conditions....................... Thermal Information .................................................. Electrical Characteristics........................................... Typical Characteristics .............................................. Detailed Description .............................................. 8 7.1 Overview ................................................................... 8 7.2 Functional Block Diagram ......................................... 8 7.3 Feature Description................................................... 9 7.4 Device Functional Modes........................................ 11 8 Application and Implementation ........................ 12 8.1 Application Information............................................ 12 8.2 Typical Applications ................................................ 15 9 Power Supply Recommendations...................... 22 10 Layout................................................................... 22 10.1 Layout Guidelines ................................................. 22 10.2 Layout Example ................................................... 22 11 Device and Documentation Support ................. 23 11.1 11.2 11.3 11.4 11.5 Receiving Notification of Documentation Updates Community Resources.......................................... Trademarks ........................................................... Electrostatic Discharge Caution ............................ Glossary ................................................................ 23 23 23 23 23 12 Mechanical, Packaging, and Orderable Information ........................................................... 23 4 Revision History NOTE: Page numbers for previous revisions may differ from page numbers in the current version. Changes from Revision D (March 2013) to Revision E Page * Added Applications section, ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section................................................................ 1 * Changed Junction to Ambient, RJA, values in Thermal Information table From: 140 To: 105.7 (SOIC) and From: 40 To: 37.1 (WSON) .................................................................................................................................................................... 4 * Changed Junction to Case, JC, values in Thermal Information table From: 32 To: 50.8 (SOIC) and From: 4.5 To: 25.8 (WSON) .......................................................................................................................................................................... 4 Changes from Revision C (March 2013) to Revision D * 2 Page Changed layout of National Semiconductor Data Sheet to TI format .................................................................................... 1 Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 5 Pin Configuration and Functions D Package 8-Pin SOIC Top View NGT Package 8-Pin WSON Top View SW 1 8 EN VIN 2 7 COMP VCC 3 6 FB GND 4 5 RT COMP 1 EN 2 8 FB 7 RT EP SW 3 6 GND VIN 4 5 VCC Not to scale Not to scale Pin Functions PIN TYPE (1) DESCRIPTION 1 O Open drain output of the internal error amplifier: the loop compensation network must be connected between the COMP pin and the FB pin. COMP pullup is provided by an internal 5-k resistor which may be used to bias an opto-coupler transistor (while FB is grounded) for isolated ground applications. 8 2 I Enable and undervoltage lockout or shutdown input: an external voltage divider can be used to set the line undervoltage lockout threshold. If the EN pin is left unconnected, a 6-A pullup current source pulls the EN pin high to enable the regulator. EP -- EP -- Exposed pad (WSON only): exposed metal pad on the underside of the package with a resistive connection to pin 6. It is recommended to connect this pad to the PCB ground plane to improve heat dissipation. FB 6 8 I Feedback input from the regulated output voltage: this pin is connected to the inverting input of the internal error amplifier. The 1.26-V reference is internally connected to the non-inverting input of the error amplifier. GND 4 6 G Ground: internal reference for the regulator control functions and the power MOSFET current sense resistor connection. RT 5 7 I Oscillator frequency programming and optional synchronization pulse input: the internal oscillator is set with a resistor, between this pin and the GND pin. The recommended frequency range is 50 KHz to 1.5 MHz. The RT pin can accept synchronization pulses from an external clock. A 100-pF capacitor is recommended for coupling the synchronizing clock to the RT pin. SW 1 3 I Switch pin: the drain terminal of the internal power MOSFET. VIN 2 4 P Input supply pin: nominal operating range is 3.1 V to 75 V. VCC 3 5 P Bias regulator output, or input for external bias supply: VCC tracks VIN up to 6.9 V. Above VIN = 6.9 V, VCC is regulated to 6.9 V. A 0.47-F or greater ceramic decoupling capacitor is required. An external voltage (7 V to 12 V) can be applied to this pin which disables the internal VCC regulator to reduce internal power dissipation and improve converter efficiency. NAME SOIC WSON COMP 7 EN (1) G = Ground, I = Input, O = Output, P = Power Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 3 LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com 6 Specifications 6.1 Absolute Maximum Ratings over operating free-air temperature range (unless otherwise noted) (1) MIN VIN to GND SW to GND (steady state) -0.3 VCC, EN to GND COMP, FB, RT to GND -0.3 Maximum junction temperature, TJ-MAX Storage temperature, Tstg (1) -65 MAX UNIT 76 V 76 V 14 V 7 V 150 C 150 C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. 6.2 ESD Ratings VALUE V(ESD) (1) (2) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) 2000 Charged-device model (CDM), per JEDEC specification JESD22-C101 (2) 750 UNIT V JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process. JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process. 6.3 Recommended Operating Conditions over operating free-air temperature range (unless otherwise noted) MIN MAX UNIT VIN 3.1 75 V Operating junction temperature -40 125 C 6.4 Thermal Information LM5002 THERMAL METRIC (1) D (SOIC) NGT (WSON) 8 PINS 8 PINS UNIT RJA Junction-to-ambient thermal resistance 105.7 37.1 C/W RJC(top) Junction-to-case (top) thermal resistance 50.8 25.8 C/W RJB Junction-to-board thermal resistance 46.1 14.2 C/W JT Junction-to-top characterization parameter 8.2 0.2 C/W JB Junction-to-board characterization parameter 45.6 14.4 C/W RJC(bot) Junction-to-case (bottom) thermal resistance -- 3.8 C/W (1) 4 For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report. Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 6.5 Electrical Characteristics Typical values at TJ = 25C, minimum and maximum values at TJ = -40C to 125C, VVIN = 10 V, and RRT = 48.7 k (unless otherwise noted) (1) PARAMETER TEST CONDITIONS MIN TYP MAX 7.15 UNIT STARTUP REGULATOR VVCC-REG VCC regulator output 6.55 6.85 VCC current limit VVCC = 6 V 15 20 VCC UVLO threshold VVCC increasing 2.6 2.8 VCC undervoltage hysteresis V mA 3 0.1 V V IIN Bias current VFB = 1.5 V 3.1 4.5 mA IQ Shutdown current (IIN) VEN = 0 V 95 130 A 0.45 0.65 V EN THRESHOLDS EN shutdown threshold VEN increasing 0.25 EN shutdown hysteresis EN standby threshold 0.1 VEN increasing 1.2 EN standby hysteresis EN current source 1.26 V 1.32 V 0.1 V 6 A MOSFET CHARACTERISTICS MOSFET RDS(ON) plus current sense resistance ID = 0.25 A 850 1600 MOSFET leakage current VSW = 75 V 0.05 5 MOSFET gate charge VVCC = 6.9 V 2.4 m A nC CURRENT LIMIT ILIM Cycle by cycle current limit 0.4 Cycle by cycle current limit delay 0.5 0.6 A 100 200 ns OSCILLATOR FSW1 Frequency1 RRT = 48.7 k 225 260 295 KHz FSW2 Frequency2 RRT = 15.8 k 660 780 900 KHz VRT-SYNC SYNC threshold 2.2 2.6 3.2 V SYNC pulse width minimum VRT > VRT-SYNC + 0.5 V 15 ns PWM COMPARATOR Maximum duty cycle VCOMP-OS 80% 85% Minimum ON-time VCOMP > VCOMP-OS 25 Minimum ON-time VCOMP < VCOMP-OS 0 COMP to PWM comparator offset 90% ns ns 0.9 1.3 1.55 1.241 1.26 1.279 V ERROR AMPLIFIER VFB-REF Feedback reference voltage Internal reference and VFB = VCOMP V FB bias current 10 nA DC gain 72 dB COMP sink current VCOMP = 250 mV 2.5 COMP short circuit current VFB = 0 V and VCOMP = 0 V 0.9 1.2 1.5 mA mA COMP open circuit voltage VFB = 0 V 4.8 5.5 6.2 V COMP to SW delay 42 ns Unity gain bandwidth 3 MHz THERMAL SHUTDOWN TSD (1) Thermal shutdown threshold 165 C Thermal shutdown hysteresis 20 C Min and Max limits are 100% production tested at 25C. Limits over the operating temperature range are ensured through correlation using Statistical Quality Control (SQC) methods. Limits are used to calculate TI's Average Outgoing Quality Level (AOQL). Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 5 LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com 6.6 Typical Characteristics 6 Figure 1. Efficiency, Boost Converter Figure 2. VFB vs Temperature Figure 3. IQ (Non-Switching) vs VIN Figure 4. VCC vs VIN Figure 5. RDS(ON) vs VCC Figure 6. RDS(ON) vs Temperature Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 Typical Characteristics (continued) Figure 7. ILIM vs VCC Figure 8. ILIM vs VCC vs Temperature Figure 9. FSW vs RRT Figure 10. FSW vs Temperature Figure 11. FSW vs VCC Figure 12. IEN vs VVIN vs Temperature Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 7 LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com 7 Detailed Description 7.1 Overview The LM5002 high-voltage switching regulator features all the functions necessary to implement an efficient boost, flyback, SEPIC or forward current-mode power converter. The operation can be best understood by referring to the block diagram. At the start of each cycle, the oscillator sets the driver logic and turns on the power MOSFET to conduct current through the inductor or transformer. The peak current in the MOSFET is controlled by the voltage at the COMP pin. The COMP voltage increases with larger loads and decrease with smaller loads. This voltage is compared with the sum of a voltage proportional to the power MOSFET current and an internally generated slope compensation ramp. Slope compensation is used in current mode PWM architectures to eliminate subharmonic current oscillation that occurs with static duty cycles greater than 50%. When the summed signal exceeds the COMP voltage, the PWM comparator resets the driver logic, turning off the power MOSFET. The driver logic is then set by the oscillator at the end of the switching cycle to initiate the next power period. The LM5002 has dedicated protection circuitry to protect the IC from abnormal operating conditions. Cycle-bycycle current limiting prevents the power MOSFET current from exceeding 0.5A. This feature can also be used to soft start the regulator. Thermal shutdown circuitry holds the driver logic in reset when the die temperature reaches 165C, and returns to normal operation when the die temperature drops by approximately 20C. The EN pin can be used as an input voltage undervoltage lockout (UVLO) during start-up to prevent operation with less than the minimum desired input voltage. 7.2 Functional Block Diagram HV-LDO VIN VCC +6.9 V 6 PA + Disable - 0.45 V + - EN REFERENCE GENERATOR SHUTDOWN +5 V 1.26 V Disable 1.26 V STANDBY + VCC 2.8 V UVLO ENABLE + THERMAL STANDBY (165 oC) ENABLE RT SW CLK OSCILLATOR WITH SYNC CAPABILITY MAX DUTY ENABLE RAMP VCC SLOPE COMP RAMP 450 mV DRIVER 0 RAMP + CS x 0.7 +5 V CLK 1.26 V S 5k + - FB Q PWM R 1.3 V 1.5 V - COMP CS ENABLE CURRENT LIMIT Av = 30 CS + + - CLK ( Leading Edge Blanking) CURRENT SENSE 100 m: GND Copyright (c) 2016, Texas Instruments Incorporated 8 Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 7.3 Feature Description 7.3.1 High Voltage VCC Regulator The LM5002 VCC low dropout (LDO) regulator allows the LM5002 to operate at the lowest possible input voltage. The VCC pin voltage is very nearly equal to the input voltage from 2.8 V up to approximately 6.9 V. As the input voltage continues to increase, the VCC voltage is regulated at the 6.9 V set-point. The total input operating range of the VCC LDO regulator is 3.1 V to 75 V. The output of the VCC regulator is current limited to 20 mA. During power-up, the VCC regulator supplies current into the required decoupling capacitor (0.47 F or greater ceramic capacitor) at the VCC pin. When the VCC voltage exceeds the VCC UVLO threshold of 2.8 V and the EN pin is greater than 1.26 V the PWM controller is enabled and switching begins. The controller remains enabled until VCC falls below 2.7 V or the EN pin falls below 1.16 V. An auxiliary supply voltage can be applied to the VCC pin to reduce the IC power dissipation. If the auxiliary voltage is greater than 6.9 V, the internal regulator essentially shuts-off, and internal power dissipation is decreased by the VIN voltage times the operating current. The overall converter efficiency also improves if the VIN voltage is much higher than the auxiliary voltage. Do not exceed 14 V with an externally applied VCC voltage. The VCC regulator series pass MOSFET includes a body diode (see Functional Block Diagram) between VCC and VIN that must not be forward biased in normal operation. Therefore, the auxiliary VCC voltage must never exceed the VIN voltage. In high voltage applications take extra care to ensure the VIN pin does not exceed the absolute maximum voltage rating of 76 V. Voltage ringing on the VIN line during line transients that exceeds the Absolute Maximum Ratings can damage the IC. Both careful PCB layout and the use of quality bypass capacitors placed close to the VIN and GND pins are essential. 7.3.2 Oscillator A single external resistor connected between RT and GND pins sets the LM5002 oscillator frequency. To set a desired oscillator frequency (FSW), the necessary value for the RT resistor can be calculated with Equation 1. 9 RT = 13.1 x 10 x 1 - 83 ns FSW (1) The tolerance of the external resistor and the frequency tolerance indicated in the Electrical Characteristics must be taken into account when determining the worst case frequency range. 7.3.3 External Synchronization The LM5002 can be synchronized to the rising edge of an external clock. The external clock must have a higher frequency than the free running oscillator frequency set by the RT resistor. The clock signal must be coupled through a 100-pF capacitor into the RT pin. A peak voltage level greater than 2.6 V at the RT pin is required for detection of the sync pulse. The DC voltage across the RT resistor is internally regulated at 1.5 V. The negative portion of the AC voltage of the synchronizing clock is clamped to this 1.5 V by an amplifier inside the LM5002 with approximately 100- output impedance. Therefore, the AC pulse superimposed on the RT resistor must have positive pulse amplitude of 1.1 V or greater to successfully synchronize the oscillator. The sync pulse width measured at the RT pin must have a duration greater than 15 ns and less than 5% of the switching period. The sync pulse rising edge initiates the internal CLK signal rising edge, which turns off the power MOSFET. The RT resistor is always required, whether the oscillator is free running or externally synchronized. Place the RT resistor very close to the device and connected directly to the RT and GND pins of the LM5002. 7.3.4 Enable and Standby The LM5002 contains a dual level Enable circuit. When the EN pin voltage is below 450 mV, the IC is in a low current shutdown mode with the VCC LDO disabled. When the EN pin voltage is raised above the shutdown threshold but below the 1.26-V standby threshold, the VCC LDO regulator is enabled, while the remainder of the IC is disabled. When the EN pin voltage is raised above the 1.26-V standby threshold, all functions are enabled and normal operation begins. An internal 6-A current source pulls up the EN pin to activate the IC when the EN pin is left disconnected. Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 9 LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com Feature Description (continued) 7.3.5 Error Amplifier and PWM Comparator An internal high-gain error amplifier generates an error signal proportional to the difference between the regulated output voltage and an internal precision reference. The output of the error amplifier is connected to the COMP pin allowing the user to add loop compensation, typically a Type-II network, as illustrated in Figure 13. This network creates a low-frequency pole that rolls off the high DC gain of the amplifier, which is necessary to accurately regulate the output voltage. FDC_POLE is the closed-loop unity gain (0 dB) frequency of this pole. A zero provides phase boost near the closed-loop unity gain frequency, and a high-frequency pole attenuates switching noise. The PWM comparator compares the current sense signal from the current sense amplifier to the error amplifier output voltage at the COMP pin. FDC_ POLE = 1 2S x R2 x C2 F ZERO = VOUT F POLE = R1 1 2S x R1 x (C1 + C2 ) 1 C1 x C2 * 2S x R2 x C1 + C2 (c) 5V 1.26 V PWM 5k FB 1.3 V C1 COMP R2 R FEEDBACK C2 LM5002 Copyright (c) 2016, Texas Instruments Incorporated Figure 13. Type II Compensator When isolation between primary and secondary circuits is required, the Error Amplifier is usually disabled by connecting the FB pin to GND. This allows the COMP pin to be driven directly by the collector of an opto-coupler. In isolated designs the external error amplifier is placed on the secondary circuit and drives the opto-coupler LED. The compensation network is connected to the secondary side error amplifier. An example of an isolated regulator with an opto-coupler is shown in Figure 19. 7.3.6 Current Amplifier and Slope Compensation The LM5002 employs peak current-mode control that also provides a cycle-by-cycle overcurrent protection feature. An internal 100-m current sense resistor measures the current in the power MOSFET source. The sense resistor voltage is amplified 30 times to provide a 3 V/A signal into the current limit comparator. Current limiting is initiated if the internal current limit comparator input exceeds the 1.5-V threshold, corresponding to 0.5 A. When the current limit comparator is triggered, the SW output pin immediately switches to a high impedance state. The current sense signal is reduced to a scale factor of 2.1 V/A for the PWM comparator signal. The signal is then summed with a 450-mV peak slope compensation ramp. The combined signal provides the PWM comparator with a control signal that reaches 1.5 V when the MOSFET current is 0.5 A. For duty cycles greater than 50%, current mode control circuits are subject to subharmonic oscillation (alternating between short and long PWM pulses every other cycle). Adding a fixed slope voltage ramp signal (slope compensation) to the current sense signal prevents this oscillation. The 450-mV ramp (zero volts when the power MOSFET turns on, and 450 mV at the end of the PWM clock cycle) adds a fixed slope to the current sense ramp to prevent oscillation. 10 Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 Feature Description (continued) To prevent erratic operation at low duty cycle, a leading edge blanking circuit attenuates the current sense signal when the power MOSFET is turned on. When the MOSFET is initially turned on, current spikes from the power MOSFET drain-source and gate-source capacitances flow through the current sense resistor. These transient currents normally cease within 50 ns with proper selection of rectifier diodes and proper PCB layout. 7.3.7 Power MOSFET The LM5002 switching regulator includes an N-Channel MOSFET with 850-m ON-resistance. The ONresistance of the LM5002 MOSFET varies with temperature as shown in Typical Characteristics. The typical total gate charge for the MOSFET is 2.4 nC which is supplied from the VCC pin when the MOSFET is turned on. 7.4 Device Functional Modes 7.4.1 Thermal Protection Internal thermal shutdown circuitry is provided to protect the IC in the event the maximum junction temperature is exceeded. When the 165C junction temperature threshold is reached, the regulator is forced into a low power standby state, disabling all functions except the VCC regulator. Thermal hysteresis allows the IC to cool down before it is re-enabled. Note that because the VCC regulator remains functional during this period, the soft-start circuit shown in Figure 17 must be augmented if soft start from thermal shutdown state is required. Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 11 LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com 8 Application and Implementation NOTE Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI's customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality. 8.1 Application Information The following information is intended to provide guidelines for the power supply designer using the LM5002. 8.1.1 VIN The voltage applied to the VIN pin can vary within the range of 3.1 V to 75 V. The current into the VIN pin depends primarily on the gate charge of the power MOSFET, the switching frequency, and any external load on the VCC pin. It is recommended to use the filter shown in Figure 14 to suppress transients that may occur at the input supply. This is particularly important when VIN is operated close to the maximum operating rating of the LM5002. When power is applied and the VIN voltage exceeds 2.8 V with the EN pin voltage greater than 0.45 V, the VCC regulator is enabled, supplying current into the external capacitor connected to the VCC pin. When the VIN voltage is between 2.8 V and 6.9 V, the VCC voltage is approximately equal to the VIN voltage. When the voltage on the VCC pin exceeds 6.9 V, the VCC pin voltage is regulated at 6.9 V. In typical flyback applications, an auxiliary transformer winding is connected through a diode to the VCC pin. This winding must raise the VCC voltage above 6.9 V to shut off the internal start-up regulator. The current requirements from this winding are relatively small, typically less than 20 mA. If the VIN voltage is much higher than the auxiliary voltage, the auxiliary winding significantly improves the conversion efficiency. It also reduces the power dissipation within the LM5002. The externally applied VCC voltage must never exceed 14 V. Also the applied VCC must never exceed the VIN voltage to avoid reverse current through the internal VCC to VIN diode shown in the LM5002 Functional Block Diagram. VPWR 10 VIN LM 5002 0.1 PF Copyright (c) 2016, Texas Instruments Incorporated Figure 14. Input Transient Protection 8.1.2 SW PIN Attention must be given to the PCB layout for the SW pin that connects to the power MOSFET drain. Energy can be stored in parasitic inductance and capacitance that causes switching spikes that negatively affect efficiency, and conducted and radiated emissions. These connections must be as short as possible to reduce inductance and as wide as possible to reduce resistance. The loop area, defined by the SW and GND pin connections, the transformer or inductor terminals, and their respective return paths, must be minimized. 12 Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 Application Information (continued) 8.1.3 EN or UVLO Voltage Divider Selection An external setpoint resistor divider from VIN to GND can be used to determine the minimum operating input range of the regulator. The divider must be designed such that the EN pin exceeds the 1.26-V standby threshold when VIN is in the desired operating range. The internal 6-A current source must be included when determining the resistor values. The shutdown and standby thresholds have 100-mV hysteresis to prevent noise from toggling between modes. When the VIN voltage is below 3.5 VDC during start-up and the operating temperature is below -20C, the EN pin must have a pullup resistor that provides 2 A or greater current. The EN pin is internally protected by a 6-V Zener diode through a 1-k resistor. The enabling voltage may exceed the Zener voltage, however the Zener current must be limited to less than 4 mA. Two dedicated comparators connected to the EN pin are used to detect undervoltage and shutdown conditions. When the EN pin voltage is below 0.45 V, the controller is in a low-current shutdown mode where the VIN current is reduced to 95 A. For an EN pin voltage greater than 0.45 V but less than 1.26 V, the controller is in standby mode, with all internal circuits operational, but the PWM gate driver signal is blocked. Once the EN pin voltage is greater than 1.26 V, the controller is fully enabled. Two external resistors can be used to program the minimum operational voltage for the power converter as shown in Figure 15. When the EN pin voltage falls below the 1.26 V threshold, an internal 100 mV threshold hysteresis prevents noise from toggling the state, so the voltage must be reduced to 1.16 V to transition to standby. Resistance values for R1 and R2 can be determined from Equation 2 and Equation 3. VPWR - 1.26V R1 = R2 = IDIVIDER (2) 1.26V IDIVIDER + 6 PA where: * * VPWR is the desired turnon voltage IDIVIDER is an arbitrary current through R1 and R2 (3) For example, if the LM5002 is to be enabled when VPWR reaches 16 V, IDIVIDER could be chosen as 501 A that sets R1 to 29.4 k and R2 to 2.49 k. The voltage at the EN pin must not exceed 10 V unless the current into the 6 V protection Zener diode is limited below 4 mA. The EN pin voltage must not exceed 14 V at any time. Be sure to check both the power and voltage rating (some 0603 resistors are rated as low as 50 V) for the selected R1 resistor. VIN VPWR LM 5002 6 PA R1 EN R2 1.26 V 0.45 V Disable PWM Controller Disable VCC Regulator Copyright (c) 2016, Texas Instruments Incorporated Figure 15. Basic EN (UVLO) Configuration Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 13 LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com Application Information (continued) Remote configuration of the LM5002's operational modes can be accomplished with open drain device(s) connected to the EN pin as shown in Figure 16. A MOSFET or an NPN transistor connected to the EN pin can force the regulator into the low power off state. Adding a PN diode in the drain (or collector) provides the offset to achieve the standby state. The advantage of standby is that the VCC LDO is not disabled and external circuitry powered by VCC remains functional. LM 5002 VPWR R1 1.26 V STANDBY EN 0.45 V R2 OFF STANDBY OFF Copyright (c) 2016, Texas Instruments Incorporated Figure 16. Remote Standby and Disable Control 8.1.4 Soft Start Soft start (SS) can be implemented with an external capacitor connected to COMP through a diode as shown in Figure 17. The COMP discharge MOSFET conducts during Shutdown and Standby modes to keep the COMP voltage below the PWM offset (1.3 V), which inhibits PWM pulses. The error amplifier attempts to raise the COMP voltage after the EN pin exceeds the 1.26 V standby threshold. Because the error amplifier output can only sink current, the internal COMP pullup resistor (approximately 5 k) supplies the charging current to the SS capacitor. The SS capacitor causes the COMP voltage to gradually increase until the output voltage achieves regulation and FB assumes control of the COMP and the PWM duty cycle. The SS capacitor continues charging through a large resistance, RSS, preventing the SS circuit from interfering with the normal error amplifier function. During shutdown, the VCC diode discharges the SS capacitor. VCC 5V VOUT 1.26 V 5k PWM FB 1.3 V COMP SHUTDOWN and STANDBY RSS SOFT- START CAPACITOR LM 5002 Copyright (c) 2016, Texas Instruments Incorporated Figure 17. Soft-Start Circuit 14 Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 8.2 Typical Applications Figure 18, Figure 19, Figure 20, and Figure 21 present examples of a non-isolated flyback, isolated flyback, boost, 24-V SEPIC, and a 12-V automotive range SEPIC converters utilizing the LM5002 switching regulator. 8.2.1 Non-Isolated Flyback Regulator VCC VIN = 16 V 42 V D1 T1 LPRI = 300 H 8:3:2 D2 C1 4. 7 F VOUT = 5 V IOUT = 500 mA C4 100 F C5 820 pF EN R2 6.04 k C2 100 pF R3 52.3 k VIN EN RT GND LM5002 R1 60.4k C6 0.47 F SW COMP FB VCC R5 10.2 k R4 7.5 k VCC R6 3.40 k C3 1 F SYNC Copyright (c) 2016, Texas Instruments Incorporated Figure 18. Non-Isolated Flyback Schematic 8.2.1.1 Design Requirements The non-isolated flyback converter shown in Figure 18 uses the internal voltage reference for the regulation setpoint. The output is 5 V at 500 mA while the input voltage can vary from 16 V to 42 V. The switching frequency is set to 250 kHz. An auxiliary winding on transformer (T1) provides 7.5 V to power the LM5002 when the output is in regulation. This disables the internal high-voltage VCC LDO regulator and improves efficiency. The input undervoltage threshold is 13.9 V. The converter can be shut down by driving the EN input below 1.26 V with an open-collector or open-drain transistor. An external synchronizing frequency can be applied to the SYNC input. An optional soft-start circuit is connected to the COMP pin input. When power is applied, the softstart capacitor (C7) is discharged and limits the voltage applied to the PWM comparator by the internal error amplifier. The internal approximate 5-k COMP pullup resistor charges the soft-start capacitor until regulation is achieved. The VCC pullup resistor (R7) continues to charge C7 so that the soft-start circuit does not affect the compensation network in normal operation. If the output capacitance is small, the soft-start circuit can be adjusted to limit the power-on output voltage overshoot. If the output capacitance is sufficiently large, no soft-start circuit is required because the LM5002 gradually charges the output capacitor by current limiting at approximately 500 mA (ILIM) until regulation is achieved. 8.2.1.2 Detailed Design Procedure 8.2.1.2.1 Switching Frequency The RT (R3) can be found using Equation 1. For 250-kHz operation, a value of 51.3 k was calculated. A 52.3-k resistor is selected as the closest available value. 8.2.1.2.2 Flyback Transformer Two things require consideration when specifying a flyback transformer. First, the turns ratio to determine the duty cyle D (MOSFET on-time compared to the switching period). Second, the primary inductacne (LPRI) to determine the current sense ramp for current-mode control. To start, the primary inductance in continous current mode (CCM) is designed to provide a ramp during the MOSFET on-time of around 30% of the full load MOSFET current. This produces a good signal-to-noise ratio for current mode control. Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 15 LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com Typical Applications (continued) The transfer function of a flyback power stage is Equation 4. VOUT D NSEC x VIN 1 D NPRI where: * * * * * VIN is the input voltage VOUT is the secondary output voltage D is the duty cycle of the MOSFET for one switching cycle NPRI is the number of turns on the primary winding of the transformer NSEC is the number of turns on the secondary winding of the transformer (4) The duty cycle can be derived as shown in Equation 5. VOUT D VINu NSEC VOUT NPRI (5) And the approximate turns ratio is given by Equation 6. NSEC VOUT u (1 D) NPRI VIN u D (6) The primary inducance (LPRI) is calculated using Equation 7. 1 VIN u D u fsw LPRI N RR u IOUT(MAX) u SEC NPRI where: * * LPRI is the transformer inductance referenced to the primary side RR is the ripple ratio of the reflected secondary output current (ypically between 30% and 40%) (7) The auxillary winding turns ratio can be found with Equation 8. V NAUX NSEC u AUX VOUT where: * * NAUX is the number of turns on the auxiliary winding of the transformer VAUX is the desired VCC voltage (8) The CCM duty cycle can be designed for 50% with minimum input voltage. Using the turns ratio of the secondary winding to the primay winding can be found to be 0.313. Rounding to a whole number of turns results in a turns ratio of 0.375. The auxillary winding of the transformer can be used to supply the VCC voltage to the LM5002, resulting in better total efficiency by disabling the internal high voltage VCC regulator. To disable the VCC regulator the exteranlly supplied voltage must be greater than 7 V, thus a target voltage of 8 V is selected. The number of turns on the auxillary winding can be found with , resulting in a turns ratio of the auxillary winding to the secondary winding of 0.6. The primary inductance can now be solved for using . Assuming that VIN is at the minimum specified value and the ripple ratio (RR) is 35% the primary inductance is calculated to be 217 H. Based on avaliable transformers a 300 H primary inductacne was selected. 16 Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 Typical Applications (continued) 8.2.1.2.3 Peak MOSFET Current The peak MOSFET current is determined with Equation 9. 1 VIN u D u fsw VOUT u IOUT IPRI(PEAK) 2 u LPRI VIN u Ku D where: * * fsw is the switching frequency is the efficiency of the converter (9) The maximum peak MOSFET current occurs when VIN is at its minimum specified voltage. Equation 9 is used to calculate the peak MOSFET current. Assuming is 90% the peak MOSFET current is calculated as 430 mA. The internal power MOSFET must withstand the input voltage plus the output voltage multiplied by the turns ratio during the off-time. This is determined with Equation 10. N * VSW VIN VOUT u PRI NSEC (c) (10) In addition, any leakage inductance of the transformer causes a turnoff voltage spike in addition to Equation 10. This voltage spike is related to the MOSFET drain-to-source capacitance as well as other parasitic capacitances. To limit the spike magnitude, use a RCD termination or a Diode-Zener clamp. 8.2.1.2.4 Output Capacitance The necessary output capacitance of the secondary side can be found using Equation 11. DMAX COUT IOUT _ MAX u fSW u 'VOUT where: * DMAX is the maximum duty cycle, which occurs at the minimum input voltage (11) Assuming that an output ripple of 15 mV is specified, states that a 60.60 F output capacitance must be selected. Accounting for capacitance equivalent series resistance (ESR) ripple, a 100 F capacitor is selected. 8.2.1.2.5 Output Diode Rating The average diode current equals the output current under normal circumstances, but the diode must be designed to handle a continuous current limit condition for the worst case: N ID(WORST CASE) ILIMIT(MOSFET) u PRI NSEC where: * ILIMIT(MOSFET) is the peak current limit of the interal MOSFET of the LM5002 The maximum reverse voltage applied to the diode occurs during the MOSFET on time in Equation 13. N VD(REVERSE) VIN(MAX) u SEC NPRI (12) (13) The diode's reverse capacitance resonates with the transformer inductance (and other parasitic elements) to some degree and causing ringing that may affect conducted and ratiated emissions compliance. Usually an RC snubber network across the diode anode and cathode cam eliminate the ringing. Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 17 LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com Typical Applications (continued) 8.2.1.2.6 Power Stage Analysis In any switch-mode topology that has the power MOSFET between the inductor and the output capacitor (boost, buck-boost, Flyback, SEPIC, and so on) a Right Half-Plane Zero (RHPZ) is produced by the power stage in the loop transfer function during Continuous Conduction Mode (CCM). If the topology is operated in Discontinuous Conduction Mode (DCM), the RHPZ does not exist. It is a function of the duty cycle, load and inductance, and causes an increase in loop gain while reducing the loop phase margin. A common practice is to determine the worst case RHPZ frequency and set the loop unity gain frequency below one-third of the RHPZ frequency In the Flyback topology, the equation for the RHPZ is given by Equation 14. VOUT u (1 D)2 IOUT fRHPZ N *2 2Su SEC u LPRI N (c) PRI 1/4 (14) The worst case RHPZ frequency is at the maximum load where IOUT is the highest and at minimum input voltage where the duty cycle D is the highest. Assuming these conditions fRHPZ is 24.6 kHz. The LM5002 uses slope compensation to ensure stability when the duty cycle exceeds 45%. This has the affect of adding some Voltage Mode control to this current-mode IC. The effect on the power stage (Plant) transfer function is calculated in the following equations: Inductor current slope during MOSFET ON time (Equation 15) VIN sn LPRI (15) Slope compensation ramp (Equation 16) se 450mV u fSW (16) Current-mode sampling gain (Equation 17) N 1 fMOD VIN u SEC u NPRI s s u 1 n e fSW (17) The control-to-output transfer function (GVC) using low ESR ceramic capacitors is Equation 18. D u L SEC 1 j2Sf u V 2 1 D u OUT V IOUT 1 D GVC (f) OUT u u VOUT IOUT 1 D u COUT I 1 j2Sf u OUT 2 1 D where: * LSEC is the transformer inductance referenced to the secondary side and is equal to: 2 L SEC NSEC * u LPRI (c) NPRI (19) (19) If high ESR capacitors (for example, aluminum electrolytic) are used for the output capacitance, an additional zero appears at frequency in Equation 20, which increases the gain slope by +20 dB per decade of frequency and boosts the phase 45 at FZERO(ESR) and 90 at 10 x FZERO(ESR). 1 fZERO(ESR) 2Su ESR u COUT where: * 18 ESR is the series resistance of the output capacitor Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 Typical Applications (continued) * COUT is the output capacitance (20) With these calculations, an approximate power stage Bode plot can be constructed with Equation 21. GVC (f) 2 20 u log fMOD Re GVC (f) 1/4 (c) 2 Im GVC (f) 1/4 * where: * * TGVC (f) [Re(GVC(f))] is the real portion of [Im(GVC(f))] is the imaginary portion of (21) Im GVC (f) 180 u arctan S (c) Re GVC (f) (22) * Because these equations don't take into account the various parasitic resistances and reactances present in all power converters, there is some difference between the calculated Bode plot and the gain and phase of the actual circuit. It is therefore important to measure the converter using a network analyzer to quantify the implementation and adjust where appropriate. 8.2.1.2.7 Loop Compensation The loop bandwidth and phase margin determines the response to load transients, while ensuring that the output noise level meets the requirements. A common choice of loop unity gain frequency is 5% of the switching frequency. This is simple to compensate, low noise and provides sufficient transient response for most applications. The plant bode plot is examined for gain and phase at the desired loop unity-gain frequency and the compensator is designed to adjust the loop gain and phase to meet the intended loop unity gain frequency and phase margin (typically about 55). When gain is required, the ratio of RCOMP and RFB_TOP sets the error amplifier to provide the correct amount. RCOMP A V(xo) RFB _ TOP where (in reference to Figure 18): * * RCOMP is R4 RFB_TOP is R5 (23) The phase margin is boosted by a transfer function zero at frequency given by Equation 23 and a pole at frequency given by Equation 24. 1 fZERO 2Su RCOMP u CCOMP where (in reference to ): * fPOLE(HIGH) CCOMP is C6 (24) 1 C uC * 2Su RCOMP u COMP HF (c) CCOMP CHF where (in reference to Figure 18): * CHF is C5 (25) The low frequency pole is determined with Equation 26. 1 1 fPOLE(LOW) u 2Su RFB _ TOP u CCOMP CHF A VOL where (in reference to Figure 18): * AVOL is the open loop gain of the error amplifier (26) Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 19 LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com Typical Applications (continued) Optimal regulation is achieved by setting FPOLE(LOW) as high as possible, but still permitting FZERO to insure the desired phase margin. The feedback resistors (RFB_TOP and RFB_BOTTOM) are chosen to be 10.2 k and 3.4 k respectively. These values produce a feedback signal that has a desirable signal to noise ratio. FZERO and FPOLE(HIGH) are set to be 450 Hz and 25.5 kHz respectively. Based on these values, RCOMP, CCOMP, and CHF are chosen to be 7.5 k, 0.47 F, and 820 pF respectively. These values produce a crossover frequency of approximately 3 kHz with a phase margin of 60. 8.2.2 Isolated Flyback Regulator T1 VCC VIN = 16V 42V LPRI = 160 eH 8:3:2 D1 D2 VOUT = 5V C1 4.7 eF R6 47 C4 1 eF R2 6.04k R3 52.3k VIN EN RT GND LM5002 R1 60.4k SW COMP FB VCC VCC C2 1 eF R5 560 C6 100eF IOUT = 500mA R7 10k C5 0.1 PF R4 249 R8 4.99k LM431 R9 2.20k R10 2.20k C3 1 eF Figure 19. Isolated Flyback Schematic 8.2.2.1 Design Requirements The isolated flyback converter shown in Figure 19 uses a 2.5-V voltage reference (LM431) placed on the isolated secondary side for the regulation setpoint. The LM5002 internal error amplifier is disabled by grounding the FB pin. The LM431 controls the current through the opto-coupler LED, which sets the COMP pin voltage. The R4 and C3 network boosts the phase response of the opto-coupler to increase the loop bandwidth. The output is 5 V at 500 mA and the input voltage ranges from 16 V to 42 V. The switching frequency is set to 250 kHz. 8.2.3 Boost Regulator L1 330 H VIN = 16 V 36 V D2 VOUT = 48 V IOUT = 125 mA C1 4.7 F C3 10 F R1 60.4 k R2 6.04 k SW COMP FB VCC C4 R4 2200 pF 73.2 k LM5002 R3 52.3 k VIN EN RT GND C2 1 F R5 54.9 k R6 1.47 k Copyright (c) 2016, Texas Instruments Incorporated Figure 20. Boost Schematc 8.2.3.1 Design Requirements The boost converter shown in Figure 20 uses the internal voltage reference for the regulation setpoint. The output is 48 V at 125 mA, while the input voltage can vary from 16 V to 36 V. The switching frequency is set to 250 kHz. The internal VCC regulator provides 6.9-V bias power, because there is not a simple method for creating an auxiliary voltage with the boost topology. Note that the boost topology does not provide output shortcircuit protection because the power MOSFET cannot interrupt the path between the input and the output. 20 Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 Typical Applications (continued) 8.2.4 24-V SEPIC Regulator L1 470 PH VIN = 16 V 48 V C3 10 PF D2 V OUT = 24 V I OUT = 125 mA C1 4.7 PF L2 470 PH C4 150 pF R3 52.3 k VIN EN RT GND LM5 002 R1 60.4k R2 6.04 k C6 22 F C5 R4 0.015 PF 11.5 k SW COMP FB VCC R5 11.5 k R6 634 C2 1 PF Figure 21. 24-V SEPIC Schematic 8.2.4.1 Design Requirements The 24-V SEPIC converter shown in Figure 21 uses the internal voltage reference for the regulation setpoint. The output is 24 V at 125 mA while the input voltage can vary from 16 V to 48 V. The switching frequency is set to 250 kHz. The internal VCC regulator provides 6.9-V bias power for the LM5002. An auxiliary voltage can be created by adding a winding on L2 and a diode into the VCC pin. 8.2.5 12-V Automotive SEPIC Regulator L1 100 PH VIN = 3.1 V 60 V C3 4.7 PF C1 2.2 PF VOUT = 12 V D2 L2 100 PH IOUT = 25 mA C6 22 eF NC R1 15.8 k VIN EN RT GND LM5002 C4 150 pF SW COMP FB VCC R2 C5 0.015 PF 11.5 k C2 1 PF R3 11.5 k R4 1.33 k Copyright (c) 2016, Texas Instruments Incorporated Figure 22. 12-V SEPIC Schematic 8.2.5.1 Design Requirements The 12-V automotive SEPIC converter shown in Figure 22 uses the internal bandgap voltage reference for the regulation setpoint. The output is 12 V at 25 mA while the input voltage can vary from 3.1 V to 60 V. The output current rating can be increased if the minimum VIN voltage requirement is increased. The switching frequency is set to 750 kHz. The internal VCC regulator provides 6.9-V bias power for the LM5002. The output voltage can be used as an auxiliary voltage if the nominal VIN voltage is greater than 12 V by adding a diode from the output into the VCC pin. In this configuration, the minimum input voltage must be greater than 12 V to prevent the internal VCC to VIN diode from conducting. If the applied VCC voltage exceeds the minimum VIN voltage, then an external blocking diode is required between the VIN pin and the power source to block current flow from VCC to the input supply. Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 21 LM5002 SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 www.ti.com 9 Power Supply Recommendations The LM5002 is a power management device. The power supply for the device is any DC voltage source within the specified input voltage range (see Design Requirements). 10 Layout 10.1 Layout Guidelines The LM5002 current sense and PWM comparators are very fast and may respond to short duration noise pulses. The components at the SW, COMP, EN and the RT pins must be as physically close as possible to the IC, thereby minimizing noise pickup on the PCB tracks. The SW pin of the LM5002 must have a short, wide conductor to the power path inductors, transformers and capacitors to minimize parasitic inductance that reduces efficiency and increases conducted and radiated noise. Ceramic decoupling capacitors are recommended between the VIN and GND pins and between the VCC and GND pins. Use short, direct connections to avoid clock jitter due to ground voltage differentials. Small package surface mount X7R or X5R capacitors are preferred for high-frequency performance and limited variation over temperature and applied voltage. If an application using the LM5002 results high junction temperatures during normal operation, multiple vias from the GND pin to a PCB ground plane help conduct heat away from the IC. Judicious positioning of the PCB within the end product, along with use of any available air flow helps reduce the junction temperatures. If using forced air cooling, avoid placing the LM5002 in the air flow shadow of large components, such as input capacitors, inductors or transformers. 10.2 Layout Example T1 VCC D1 D2 VOUT C3 GND VIN C4 C1 VIN VCC GND SW CIN GND RIN GND LM5002 R6 R2 R3 C5 R4 C8 R1 GND Via to GND Via to VCC Via to VIN Via to VIN pin R5 Copyright (c) 2016, Texas Instruments Incorporated Figure 23. Layout Example for Figure 18 22 Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 LM5002 www.ti.com SNVS496E - JANUARY 2007 - REVISED DECEMBER 2016 11 Device and Documentation Support 11.1 Receiving Notification of Documentation Updates To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper right corner, click on Alert me to register and receive a weekly digest of any product information that has changed. For change details, review the revision history included in any revised document. 11.2 Community Resources The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of Use. TI E2ETM Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help solve problems with fellow engineers. Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and contact information for technical support. 11.3 Trademarks E2E is a trademark of Texas Instruments. All other trademarks are the property of their respective owners. 11.4 Electrostatic Discharge Caution These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. 11.5 Glossary SLYZ022 -- TI Glossary. This glossary lists and explains terms, acronyms, and definitions. 12 Mechanical, Packaging, and Orderable Information The following pages include mechanical, packaging, and orderable information. This information is the most current data available for the designated devices. This data is subject to change without notice and revision of this document. For browser-based versions of this data sheet, refer to the left-hand navigation. Submit Documentation Feedback Copyright (c) 2007-2016, Texas Instruments Incorporated Product Folder Links: LM5002 23 PACKAGE OPTION ADDENDUM www.ti.com 23-Feb-2016 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Pins Package Drawing Qty Eco Plan Lead/Ball Finish MSL Peak Temp (2) (6) (3) Op Temp (C) Device Marking (4/5) LM5002MA/NOPB ACTIVE SOIC D 8 95 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 L5002 MA LM5002MAX NRND SOIC D 8 2500 TBD Call TI Call TI -40 to 125 L5002 MA LM5002MAX/NOPB ACTIVE SOIC D 8 2500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 L5002 MA LM5002SD/NOPB ACTIVE WSON NGT 8 1000 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LM5002 LM5002SDX/NOPB ACTIVE WSON NGT 8 4500 Green (RoHS & no Sb/Br) CU SN Level-1-260C-UNLIM -40 to 125 LM5002 (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. (4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device. (5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation of the previous line and the two combined represent the entire Device Marking for that device. Addendum-Page 1 Samples PACKAGE OPTION ADDENDUM www.ti.com 23-Feb-2016 (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. 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Addendum-Page 2 PACKAGE MATERIALS INFORMATION www.ti.com 23-Feb-2016 TAPE AND REEL INFORMATION *All dimensions are nominal Device LM5002MAX Package Package Pins Type Drawing SOIC SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LM5002MAX/NOPB SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1 LM5002SD/NOPB WSON NGT 8 1000 178.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 LM5002SDX/NOPB WSON NGT 8 4500 330.0 12.4 4.3 4.3 1.3 8.0 12.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 23-Feb-2016 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM5002MAX SOIC D 8 2500 367.0 367.0 35.0 LM5002MAX/NOPB SOIC D 8 2500 367.0 367.0 35.0 LM5002SD/NOPB WSON NGT 8 1000 210.0 185.0 35.0 LM5002SDX/NOPB WSON NGT 8 4500 367.0 367.0 35.0 Pack Materials-Page 2 MECHANICAL DATA NGT0008A SDC08A (Rev A) www.ti.com IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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