Datasheet 0.95V to VCC-1V, 0.5A/1.0A/2.0A 1ch Ultra Low Dropout Linear Regulators BD3550HFN BD3551HFN BD3552HFN General Description Key Specifications BD3550HFN, BD3551HFN and BD3552HFN are ultra low-dropout linear chipset regulators that operate from a very low input supply. They offer ideal performance in low input voltage to low output voltage applications. The input-to-output voltage difference is minimized by using a built-in N-Channel power MOSFET with a maximum ON-Resistance of RON=100m(Typ) <BD3552HFN>. By lowering the dropout voltage, the regulator realizes high output current (IOUTMAX=2.0A <BD3552HFN>) thereby, reducing conversion loss, making it comparable to a switching regulator and its power transistor, choke coil, and rectifier diode constituents. The BD3550HFN, BD3551HFN, BD3552HFN are available in significantly downsized package profiles and allow low-cost design. An external resistor allows the entire range of output voltage configurations between 0.65V and 2.7V, while the NRCS (soft start) function enables a controlled output voltage ramp-up, which can be programmed to a required power supply sequence. IN Input Voltage Range: 0.95V to VCC-1V VCC Input Voltage Range: 4.3V to 5.5V Output Voltage Range: 0.65V to 2.7V Standby Current: 0A (Typ) Operating Temperature Range: -10C to +100C Package W(Typ) x D(Typ) x H(Max) HSON8 2.90mm x 3.00mm x 0.60mm Features Internal High-Precision Reference Voltage Circuit (0.65V1%) Built-in VCC Undervoltage Lockout Circuit NRCS (soft start) Function Reduces the Magnitude of In-rush Current Internal N-Channel MOSFET Built-in Current Limit Circuit Built-in Thermal Shutdown (TSD) Circuit Tracking Function Applications Notebook computers, Desktop computers, LCD-TV, DVD, Digital appliances Lineup Maximum Output Current 0.5A 1.0A 2.0A ON-Resistance(Typ) 400m 200m 100m Product structureSilicon monolithic integrated circuit www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 Package HSON8 VCC=5V BD3550HFN BD3551HFN BD3552HFN This product has no designed protection against radioactive rays 1/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Typical Application Circuit, Block Diagram VCC VCC VCC UVLO EN Current Limit CL Reference Block IN IN VCC OUT CL UVLO TSD OUT EN FB Thermal Shutdown GATE NRCS TSD NRCS GND Pin Descriptions Pin No. 1 2 3 4 5 6 Pin Name VCC EN GATE IN OUT FB 7 NRCS 8 reverse GND FIN Pin Function Power supply pin Enable input pin Gate pin Input voltage pin Output voltage pin Reference voltage feedback pin In-rush current protection (NRCS) capacitor connection pin Ground pin Connected to heatsink and GND www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 2/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Description of Blocks 1. AMP This is an error amp that compares the reference voltage (0.65V) with FB voltage to drive the output N-Channel FET. Frequency optimization aids in attaining rapid transient response, and to support the use of ceramic capacitors on the output. AMP output voltage ranges from GND to VCC. When EN is OFF, or when UVLO is active, output goes LOW and the output of the N-Channel FET switches OFF. 2. EN The EN block controls the ON and OFF state of the regulator via the EN logic input pin. During OFF state, circuit voltage stabilizes at 0A which minimizes the current consumption during standby mode. The FET is switched ON to enable discharge of the NRCS and OUT, thereby draining the excess charge and preventing the load side of an IC from malfunctioning. Since there is no electrical connection required (e.g., between the VCC pin and the ESD prevention Diode), module operation is independent of the input sequence. 3. UVLO To prevent malfunctions that can occur during a sudden decrease in VCC, the UVLO circuit switches the output OFF, and (like the EN block) discharges NRCS and OUT. Once the UVLO threshold voltage (TYP3.80V) is reached, the power-ON reset is triggered and output is restored. 4. CURRENT LIMIT During ON state, the current limit function monitors the output current of the IC against the current limit value (2.0A or more: BD3552HFN). When output current exceeds this value, this block lowers the output current to protect the load IC. When it overcomes the over-current state, output voltage is restored to the normal value. 5. NRCS (Non Rush Current on Start-up) The soft start function is enabled by connecting an external capacitor between the NRCS pin and GND. Output ramp-up can be set for any period up to the time the NRCS pin reaches VFB (0.65V). During startup, the NRCS pin serves as a 20A (TYP) constant current source to charge the external capacitor. Output start time is calculated by formula (1) below. t C 0.65V (1) 20A Tracking sequence is possible by connecting the NRCS output to an external power supply instead of external capacitor. And then, ratio-metric sequence is also available by changing the resistor divider ratio of external power supply voltage. (See page 16) 6. TSD (Thermal Shut down) The shutdown (TSD) circuit automatically latched OFF when the chip temperature exceeds the threshold temperature after the programmed time period elapses, thus protecting the IC against "thermal runaway" and heat damage. Since the TSD circuit is designed only to shut down the IC in the occurrence of extreme heat, it is important that the Tj (max) parameter should not be exceeded in the thermal design, in order to avoid potential problems with the TSD. 7. IN The IN line acts as the major current supply line, and is connected to the output N-channel FET drain. Since there is no electrical connection (such as between the VCC pin and the ESD protection Diode) required, IN operates independent of the input sequence. However, since an output N-Channel FET body diode exists between IN and OUT, a VIN-VOUT electric (Diode) connection is present. Therefore, when output is switched ON or OFF, reverse current may flow from IN to OUT. www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 3/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Absolute Maximum Ratings (Ta=25C) Parameter Limit Symbol BD3550HFN Input Voltage 1 Input Voltage 2 Enable Input Voltage Power Dissipation 1 Power Dissipation 2 Power Dissipation 3 Operating Temperature Range Storage Temperature Range Maximum Junction Temperature VCC VIN VEN Pd1 Pd2 Pd3 Topr Tstg Tjmax BD3551HFN +6.0 (Note 1) +6.0 (Note 1) -0.3 to +6.0 0.63 (Note 2) 1.35 (Note 3) 1.75 (Note 4) -10 to +100 -55 to +150 +150 Unit BD3552HFN V V V W W W C C C (Note 1) Should not exceed Pd. (Note 2) Derate by 5.04mW/C for Ta above 25C (when mounted on a 70mm x 70mm x 1.6mm glass-epoxy board, 1-layer) On less than 0.2% (percentage occupied by copper foil. (Note 3) Derate by 10.8mW/C for Ta above25C (when mounted on a 70mm x 70mm x 1.6mm glass-epoxy board, 1-layer) On less than 7.0% (percentage occupied by copper foil. (Note 4) Derate by 14.0mW/C for Ta bove25C (when mounted on a 70mm x 70mm x 1.6mm glass-epoxy board, 1-layer) On less than 65.0% (percentage occupied by copper foil. Caution: Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated over the absolute maximum ratings. Recommended Operating Conditions (Ta=25C) Parameter Input Voltage 1 Input Voltage 2 Output Voltage Setting Range Enable Input Voltage NRCS Capacity Symbol VCC VIN VOUT VEN CNRCS Min 4.3 0.95 VFB 0 0.001 Max 5.5 VCC-1 (Note 5) 2.7 5.5 1 Unit V V V V F (Note 5) VCC and IN do not have to be implemented in the order listed. Electrical Characteristics (Unless otherwise specified, Ta=25C, VCC=5V, VEN=3V, VIN=1.8V, R1=3.9K, R2=3.3K) Limit Parameter Symbol Unit Conditions Min Typ Max Bias Current ICC 0.5 1.0 mA VCC Shutdown Mode Current IST 0 10 A VEN=0V Output Voltage Temperature Tcvo 0.01 %/C Coefficient Feedback Voltage 1 VFB1 0.643 0.650 0.657 V Feedback Voltage 2 VFB2 0.637 0.650 0.663 V Tj=-10C to +100C IOUT=0A to 1A Load Regulation Reg.L 0.5 10 mV (BD3550HFN IOUT=0A to 0.5A) Line Regulation 1 Reg.l1 0.1 0.5 %/V VCC=4.3V to 5.5V Line Regulation 2 Reg.l2 0.1 0.5 %/V VIN=1.2V to 3.3V Standby Discharge Current IDEN 1 mA VEN=0V, VOUT=1V [ENABLE] Enable Pin VENHI 2 V Input Voltage High Enable Pin VENLOW 0 0.8 V Input Voltage Low Enable Input Bias Current IEN 7 10 A VEN=3V [FEEDBACK] Feedback Pin Bias Current IFB -100 0 +100 nA [NRCS] NRCS Charge Current INRCS 14 20 26 A VNRCS=0.5V NRCS Standby Voltage VSTB 0 50 mV VEN=0V www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 4/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Electrical Characteristics - continued (Unless otherwise specified, Ta=25C, VCC=5V, VEN=3V, VIN=1.8V, R1=3.9K, R2=3.3K) Limit Parameter Symbol Unit Conditions Min Typ Max [UVLO] VCC Undervoltage Lockout VCCUVLO 3.5 3.8 4.1 V VCC: Sweep-up Threshold Voltage VCC Undervoltage Lockout VCCHYS 100 160 220 mV VCC: Sweep-down Hysteresis Voltage [AMP] Gate Source Current IGSO 1.6 mA VFB=0, VGATE=2.5V Gate Sink Current IGSI 4.7 mA VFB=VCC, VGATE=2.5V BD3550HFN IOUT 0.5 A Maximum Output BD3551HFN IOUT 1.0 A Current BD3552HFN IOUT 2.0 A IOUT=0.5A, VIN=1.2V, BD3550HFN dVOUT 200 300 mV Ta=-10C to +100C Minimum IOUT=1.0A, VIN=1.2V, BD3551HFN dVOUT 200 300 mV Dropout Voltage Ta=-10C to +100C IOUT=2.0A, VIN=1.2V, BD3552HFN dVOUT 200 300 mV Ta=-10C to +100C www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 5/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Typical Waveforms BD3550HFN VOUT 50mV/div VOUT 50mV/div 26mV 22mV IOUT 0.5A/div IOUT 0.5A/div 0.5A IOUT=0A to 1A/sec 0.5A t(10sec/div) IOUT=0A to 1A/sec Figure 1. Transient Response (0A to 0.5A) COUT=100F, CFB=1000pF t(10sec/div) Figure 2. Transient Response (0A to 0.5A) COUT=47F, CFB=1000pF VOUT 50mV/div VOUT 50mV/div 14mV 40mV IOUT 0.5A/div IOUT 0.5A/div 0.5A IOUT=0A to 1A/sec IOUT=1A to 0A/sec t(10sec/div) Figure 3. Transient Response (0A to 0.5A) COUT=22F, CFB=1000pF www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 0.5A t(100sec/div) Figure 4. Transient Response (0.5 to 0A) COUT=100F, CFB=1000pF 6/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Typical Waveforms - continued VOUT 50mV/div VOUT 50mV/div 33mV 23mV IOUT 0.5A/div IOUT 0.5A/div 0.5A IOUT=1A to 0A/sec t(100sec/div) 0.5A IOUT=1A to 0A/sec t(100sec/div) Figure 6. Transient Response (0.5A to 0A) COUT=22F, CFB=1000pF Figure 5. Transient Response (0.5A to 0A) COUT=47F, CFB=1000pF BD3551HFN VOUT 50mV/div VOUT 50mV/div 35mV IOUT 1.0A/div 46mV IOUT 1.0A/div 1.0A IOUT=0A to 1A/sec t(10sec/div) IOUT=0A to 1A/sec t(10sec/div) Figure 8. Transient Response (0A to 1.0A) COUT=47F, CFB=1000pF Figure 7. Transient Response (0A to 1.0A) COUT=100F, CFB=1000pF www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 1.0A 7/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Typical Waveforms - continued VOUT 50mV/div VOUT 50mV/div 36mV 55mV IOUT 1.0A/div IOUT 1.0A/div 1.0A IOUT=0A to 1A/sec 1.0A IOUT=1A to 0A/sec t(10sec/div) Figure 10. Transient Response (1.0A to 0A) COUT=100F, CFB=1000pF Figure 9. Transient Response (0A to 1.0A) COUT=22F, CFB=1000pF VOUT 50mV/div IOUT 1.0A/div VOUT 50mV/div 46mV IOUT=0A to 1A/ sec IOUT=0A to 1A/ sec IOUT 1.0A/div t(100sec/div) t(10 sec/div) 1.0A IOUT=1A to 0A/sec Figure 11. Transient Response (1.0A to 0A) COUT=47F, CFB=1000pF www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 56mV t(10 sec/div) 1.0A IOUT=1A to 0A/sec t(100sec/div) t(100sec/div) Figure 12. Transient Response (1.0A to 0A) COUT=22F, CFB=1000pF 8/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Typical Waveforms - continued BD3552HFN VOUT 50mV/div VOUT 50mV/div 26mV 89mV IOUT 2.0A/div IOUT 2.0A/div 2.0A IOUT=0A to 1A/sec 2.0A IOUT=0A to 1A/sec t(10sec/div) t(10sec/div) Figure 14. Transient Response (0A to 2.0A) COUT=47F, CFB=1000pF Figure 13. Transient Response (0A to 2.0A) COUT=100F, CFB=1000pF VOUT 50mV/div VOUT 50mV/div 54mV IOUT 2.0A/div 2.0A 117mV IOUT 2.0A/div 2.0A IOUT=0A to 1A/sec IOUT=1A to 0A/sec t(10sec/div) Figure 16. Transient Response (2.0A to 0A) COUT=100F, CFB=1000pF Figure 15. Transient Response (0A to 2.0A) COUT=22F, CFB=1000pF www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com t(100sec/div) 9/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Typical Waveforms - continued VOUT 50mV/div VOUT 50mV/div 83mV 117mV IOUT 2.0A/div IOUT 2.0A/div 2.0A 2.0A IOUT=1A to 0A/sec IOUT=1A to 0A/sec t(100sec/div) t(100sec/div) Figure 18. Transient Response (2.0A to 0A) COUT=22F, CFB=1000pF Figure 17. Transient Response (2.0A to 0A) COUT=47F, CFB=1000pF BD3551HFN VEN 2V/div VEN 2V/div VNRCS 2V/div VNRCS 2V/div VOUT 1V/div VOUT 1V/div t(2msec/div) t(200 sec/div) Figure 19. Waveform at Output Start www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com Figure 20. Waveform at Output OFF 10/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Typical Waveforms - continued VCC VCC VEN VEN VIN VIN VOUT VOUT VCC to VIN to VEN VIN to VCC to VEN Figure 21. Input Sequence Figure 22. Input Sequence VCC VCC VEN VEN VIN VIN VOUT VOUT VEN to VCC to VIN VCC to VEN to VIN Figure 23. Input Sequence www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com Figure 24. Input Sequence 11/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Typical Waveforms - continued VCC VCC VEN VEN VIN VIN VOUT VOUT VIN to VEN to VCC VEN to VIN to VCC Figure 25. Input Sequence www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com Figure 26. Input Sequence 12/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Typical Performance Curves 1.25 0.80 0.75 Circuit Current ICC(mA): ICC (mA) Output Voltage : VOUT (V) Vo(V) 1.23 1.21 1.19 1.17 0.70 0.65 0.60 0.55 0.50 0.45 0.40 0.35 0.30 1.15 -10 10 30 50 70 Ta() : Ta (C) Temperature -10 90 100 10 30 50 70 90 100 Ta() : Ta (C) Temperature Figure 28. Circuit Current vs Temperature Figure 27. Output Voltage vs Temperature (IOUT=0mA) 1.2 2.0 1.9 1.0 1.8 1.7 1.6 IIN (A) ISTB (A) 0.8 0.6 1.5 1.4 0.4 1.3 1.2 0.2 1.1 0.0 -60 -30 0 30 60 90 120 1.0 150 -10 Temperature : Ta (C) 30 50 70 90 100 Temperature : Ta (C) Figure 29. ISTB vs Temperature www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 10 Figure 30. IIN vs Temperature 13/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN () - 25 NRCS Charge Current : INCRS (A) 30 IINSTB (A) 25 20 15 10 5 24 23 22 21 20 19 18 17 16 15 0 -60 -30 0 30 60 90 120 -10 150 10 Temperature : Ta (C) Figure 31. IINSTB vs Temperature 50 70 90 100 Figure 32. NCRS Charge Current vs Temperature 10 Enable Input Bias Current : IEN (A) 20 Feedback Pin Bias Current : IFB (nA) 30 Temperature : Ta (C) 15 10 5 0 -5 -10 -15 -20 9 8 7 6 5 4 3 2 1 0 -10 10 30 50 70 90 -10 100 Figure 33. Feedback Pin Bias Current vs Temperature www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 10 30 50 70 90 100 Temperature : Ta (C) Temperature : Ta (C) 14/26 Figure 34. Enable Input Bias Current vs Temperature TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN () - Output ON-Resistance : RON (m) Output ON-Resistance : RON (m) 150 140 130 120 110 100 90 -10 10 30 50 70 90 100 Input Voltage 1 : VCC (V) Temperature : Ta (C) Figure 36. Output ON-Resistance vs Input Voltage 1 Figure 35. Output ON-Resistance vs Temperature (VCC=5V/VOUT=1.2V) www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 15/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Timing Chart EN ON/OFF IN VCC EN 0.65V(typ) NRCS Startup OUT t VCC ON/OFF IN UVLO Hysteresis VCC EN 0.65V(typ) NRCS Startup OUT t Tracking Sequence 1.8V Output 1.2V Output DC/DC (R1=3.9k, R2=3.3k) NRCS 1.8V OUT 1.2V Tracking sequence OUT R2 3.3k R1 1.8V Output FB 3.9k 1.2V Output Ratio-metric sequence www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 16/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Application Information 1. Evaluation Board BD3550HFN,BD3551HFN,BD3552HFN Evaluation Board Schematic VCC GND_S 1 8 GND VCC VCC SW1 C1 R8 GND EN C12 GND 2 7 NRCS C10 GND C11 GND U1 BD355XHFN (HSON8) 3 6 GATE R4 R1 GND R2 VIN_S 4 FB GND C13 VO_S 5 GND VIN Vo C4 C7 GND GND C2 C3 GND GND C6 C5 GND GND R3 C8 GND R5 GND C9 7568 4 U2 GND VCC 321 TP2 R6 TP1 R7 JPF1 GND GND GND GND JPF2 5 2 U3 GND 4 3 R9 C14 BD3550HFN,BD3551HFN,BD3552HFN Evaluation Board Standard Component List Component Rating Manufacturer Product Name Component Rating Manufacturer Product Name U1 - ROHM BD355XHFN C2 22uF KYOCERA CM32X5R226M10A C1 1F MURATA GRM188B11A105KD C13 1000pF MURATA GRM188B11H102KD C10 0.01F MURATA GRM188B11H103KD R1 3.9k ROHM MCR03EZPF3301 R8 0 - Jumper R2 3.3k ROHM MCR03EZPF3901 C5 22F KYOCERA CM32X5R226M10A BD3550HFN,BD3551HFN,BD3552HFN Evaluation Board Layout (2nd layer and 3rd layer is GND Line.) Silkscreen www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com TOP Layer 17/26 Bottom Layer TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN 2. Recommended Circuit Example VCC VEN C1 R4 1 8 2 7 3 6 GND C4 R1 FB 4 5 R2 C5 Vo(1.2V) VIN Component R1/R2 C3 C1/ C2 Recommended Value 3.9k/3.3k 22F 1F/22F C4 0.01F C5 - R4 Several k to several 10k www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com C3 C2 Programming Notes and Precautions IC output voltage can be set with a configuration formula using the values for the internal reference output voltage (VFB) and the output voltage resistors (R1, R2). Select resistance values that will avoid the impact of the FB current (100nA). The recommended total resistance value is 10K. To assure output voltage stability, make sure the OUT pin and the GND pins are connected. Output capacitors play a role in loop gain phase compensation and in minimizing output fluctuation during rapid changes in load level. Insufficient capacitance may cause oscillation, while high equivalent series resistance (ESR) will exacerbate output voltage fluctuation under rapid load change conditions. While a 22F ceramic capacitor is recomended, actual stability is highly dependent on temperature and load conditions. Also, note that connecting different types of capacitors in series may result in insufficient total phase compensation, thus causing oscillation. In light of this information, please confirm operation across a variety of temperature and load conditions. Input capacitors reduce the output impedance of the voltage supply source connected to the (VCC, IN) input pins. If the impedance of this power supply were to increase, input voltage (VCC, VIN) could become unstable, leading to oscillation or decreased ripple rejection ability. While a low-ESR 1F/22F capacitor with minimal susceptibility to temperature is recommended, stability is highly dependent on the input power supply characteristics and the substrate wiring pattern. In light of this information, please confirm operation across a variety of temperature and load conditions. The Non Rush Current on Startup (NRCS) function is built into the IC to prevent rush current from going through the load (IN to OUT) and affecting output capacitors at power supply start-up. Constant current comes from the NRCS pin when EN is HIGH or the UVLO function is deactivated. The temporary reference voltage is proportional to time, due to the current charge of the NRCS pin capacitor, and output voltage start-up is proportional to this reference voltage. Capacitors with low susceptibility to temperature are recommended, in order to ensure a stable soft-start time. This component is employed when the C3 capacitor causes, or may cause, oscillation. It provides more precise internal phase correction. It is recommended that a resistance (several k to several 10k) be put in R 4, in case negative voltage is applied in EN pin. 18/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN 3. Heat Loss In thermal design consider the temperature range wherein the IC is guaranteed to operate and apply appropriate margins. The temperature conditions that need to be considered are listed below: (1) Ambient temperature Ta can be no higher than 100C. (2) Chip junction temperature (Tj) can be no higher than 150C. Chip junction temperature can be determined as follows: Calculation based on ambient temperature (Ta) Tj Ta j a W <Reference values> j-a:HSON8 198.4C/W 1-layer substrate (copper foil density 0.2%) 92.4C/W 1-layer substrate (copper foil density 7%) 71.4C/W 2-layer substrate (copper foil density 65%) Substrate size: 70mm x 70mm x 1.6mm3 (substrate with thermal via) It is recommended to layout the VIA for heat radiation in the GND pattern of reverse (of IC) when there is the GND pattern in the inner layer (in using multiplayer substrate). This package is so small (size: 2.9mm x 3.0mm) that it is not available to layout the VIA in the bottom of IC. Spreading the pattern and being increased the number of VIA as shown in the figure below), enable to achieve superior heat radiation characteristic. (This figure is an image only. It is recommended that the VIA size and the number is designed suitable for the actual situation.). Most of the heat loss in BD3550HFN, BD3551HFN, BD3552HFN occurs at the output N-Channel FET. Power loss is determined by the total IN-OUT voltage and output current. Be sure to confirm the system input and output voltage and the output current conditions in relation to the heat dissipation characteristics of the IN and OUT in the design. Bearing in mind that heat dissipation may vary substantially depending on the substrate employed make sure to factor conditions such as substrate size into the thermal design. Power consumption (W) = Input voltage (VIN)- Output voltage (VOUT) x IOUT(Ave) Example) Where VIN=1.8V, VOUT=1.2V, IOUT(Ave) = 1A, Power consumption W 1.8 V 1.2 V 1.0 A 0.6 W www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 19/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN HSON8 [W] Power Dissipation [Pd] 2.0 (3) 1.75W 1.5 (1) Substrate (copper foil density: 0.2%...1-layer) j-a=198.4C/W (2) Substrate (copper foil density: 7%...1-layer) j-a=92.4C/W (3) Substrate (copper foil density: 65%...1-layer) j-a=71.4C /W (2) 1.35W 1.0 (1) 0.63W 0.5 0 0 25 50 75 100 125 Ambient Temperature [Ta] 150 [C] 4. Reference Landing Pattern MIE b2 D3 e E3 L2 (Unit: mm) Lead pitch Lead pitch landing length landing pitch e 0.65 MIE 2.50 l2 0.40 b2 0.35 central pad length central pad pitch D3 E3 2.90 1.90 (Note) It is recommended to design suitable for the actual application. www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 20/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN I/O Equivalent Circuits VCC VCC 1k NRCS 1k 1k 1k IN 1k 1k VCC VCC VFB 1k 1k EN OUT1 400k OUT2 50k www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 1k 21/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Operational Notes 1. Reverse Connection of Power Supply Connecting the power supply in reverse polarity can damage the IC. Take precautions against reverse polarity when connecting the power supply, such as mounting an external diode between the power supply and the IC's power supply terminals. 2. Power Supply Lines Design the PCB layout pattern to provide low impedance supply lines. Separate the ground and supply lines of the digital and analog blocks to prevent noise in the ground and supply lines of the digital block from affecting the analog block. Furthermore, connect a capacitor to ground at all power supply pins. Consider the effect of temperature and aging on the capacitance value when using electrolytic capacitors. 3. Ground Voltage Ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition. 4. Ground Wiring Pattern When using both small-signal and large-current ground traces, the two ground traces should be routed separately but connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signal ground caused by large currents. Also ensure that the ground traces of external components do not cause variations on the ground voltage. The ground lines must be as short and thick as possible to reduce line impedance. 5. Thermal Consideration Should by any chance the power dissipation rating be exceeded, the rise in temperature of the chip may result in deterioration of the properties of the chip. The absolute maximum rating of the Pd stated in this specification is when the IC is mounted on a 70mm x 70mm x 1.6mm glass epoxy board. In case of exceeding this absolute maximum rating, increase the board size and copper area to prevent exceeding the Pd rating. 6. Recommended Operating Conditions These conditions represent a range within which the expected characteristics of the IC can be approximately obtained. The electrical characteristics are guaranteed under the conditions of each parameter. 7. Inrush Current When power is first supplied to the IC, it is possible that the internal logic may be unstable and inrush current may flow instantaneously due to the internal powering sequence and delays, especially if the IC has more than one power supply. Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring, and routing of connections. 8. Operation Under Strong Electromagnetic Field Operating the IC in the presence of a strong electromagnetic field may cause the IC to malfunction. 9. Testing on Application Boards When testing the IC on an application board, connecting a capacitor directly to a low-impedance output pin may subject the IC to stress. Always discharge capacitors completely after each process or step. The IC's power supply should always be turned OFF completely before connecting or removing it from the test setup during the inspection process. To prevent damage from static discharge, ground the IC during assembly and use similar precautions during transport and storage. 10. Inter-pin Short and Mounting Errors Ensure that the direction and position are correct when mounting the IC on the PCB. Incorrect mounting may result in damaging the IC. Avoid nearby pins being shorted to each other especially to ground, power supply and output pin. Inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment) and unintentional solder bridge deposited in between pins during assembly to name a few. 11. Unused Input Terminals Input terminals of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance and extremely low capacitance. If left unconnected, the electric field from the outside can easily charge it. The small charge acquired in this way is enough to produce a significant effect on the conduction through the transistor and cause unexpected operation of the IC. So unless otherwise specified, unused input terminals should be connected to the power supply or ground line. www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 22/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Operational Notes - continued 12. Regarding Input Pins of the IC This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated. P-N junctions are formed at the intersection of the P layers with the N layers of other elements, creating a parasitic diode or transistor. For example (refer to figure below): When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode. When GND > Pin B, the P-N junction operates as a parasitic transistor. Parasitic diodes inevitably occur in the structure of the IC. The operation of parasitic diodes can result in mutual interference among circuits, operational faults, or physical damage. Therefore, conditions that cause these diodes to operate, such as applying a voltage lower than the GND voltage to an input pin (and thus to the P substrate) should be avoided. Resistor Transistor (NPN) Pin A Pin B C E Pin A N P+ P N N P+ N Pin B B Parasitic Elements N P+ N P N P+ B N C E Parasitic Elements P Substrate P Substrate GND GND Parasitic Elements GND Parasitic Elements GND N Region close-by Figure 37. Example of Monolithic IC Structure 13. Area of Safe Operation (ASO) Operate the IC such that the output voltage, output current, and power dissipation are all within the Area of Safe Operation (ASO). 14. Thermal Shutdown Circuit (TSD) This IC has a built-in thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always be within the IC's power dissipation rating. If however the rating is exceeded for a continued period, the junction temperature (Tj) will rise which will activate the TSD circuit that will turn OFF all output pins. When the Tj falls below the TSD threshold, the circuits are automatically restored to normal operation. Note that the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC from heat damage. BD3550HFN,BD3551HFN,BD3552HFN TSD on temperature [C] (typ) 175 Hysteresis temperature [C] (typ) 15 15. Output Protection Diode Please add a protection diode when a large inductance component is connected to the output terminal, and reverse-polarity power is possible at startup or in output OFF condition. (Example) OUTPUT PIN www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 23/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Ordering Information B D 3 5 5 Part Number 3550 3551 3552 x H F N Package HFN : HSON8 TR Packaging and forming specification TR: Emboss tape reel opposite draw-out side: 1 pin Marking Diagrams BD3550HFN HSON8 (TOP VIEW) Part Number Marking BD3 LOT Number 5 5 0 1PIN MARK BD3551HFN HSON8 (TOP VIEW) Part Number Marking BD3 LOT Number 5 5 1 1PIN MARK BD3552HFN HSON8 (TOP VIEW) Part Number Marking BD3 LOT Number 5 5 2 1PIN MARK www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 24/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Physical Dimension, Tape and Reel Information Package Name www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com HSON8 25/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 BD3550HFN BD3551HFN BD3552HFN Revision History Date Revision 02.Nov.2015 001 Changes New Release www.rohm.com (c) 2015 ROHM Co., Ltd. All rights reserved. TSZ2211114001 www.rohm.com 26/26 TSZ02201-0J2J0A601140-1-2 02.Nov.2015 Rev.001 Datasheet Notice Precaution on using ROHM Products 1. Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment, OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you (Note 1) , transport intend to use our Products in devices requiring extremely high reliability (such as medical equipment equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or serious damage to property ("Specific Applications"), please consult with the ROHM sales representative in advance. Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of any ROHM's Products for Specific Applications. (Note1) Medical Equipment Classification of the Specific Applications JAPAN USA EU CHINA CLASS CLASSb CLASS CLASS CLASS CLASS 2. ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate safety measures including but not limited to fail-safe design against the physical injury, damage to any property, which a failure or malfunction of our Products may cause. The following are examples of safety measures: [a] Installation of protection circuits or other protective devices to improve system safety [b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure 3. Our Products are designed and manufactured for use under standard conditions and not under any special or extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way responsible or liable for any damages, expenses or losses arising from the use of any ROHM's Products under any special or extraordinary environments or conditions. If you intend to use our Products under any special or extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of product performance, reliability, etc, prior to use, must be necessary: [a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents [b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust [c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves [e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items [f] Sealing or coating our Products with resin or other coating materials [g] Use of our Products without cleaning residue of flux (even if you use no-clean type fluxes, cleaning residue of flux is recommended); or Washing our Products by using water or water-soluble cleaning agents for cleaning residue after soldering [h] Use of the Products in places subject to dew condensation 4. The Products are not subject to radiation-proof design. 5. Please verify and confirm characteristics of the final or mounted products in using the Products. 6. In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse. is applied, confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affect product performance and reliability. 7. De-rate Power Dissipation depending on ambient temperature. When used in sealed area, confirm that it is the use in the range that does not exceed the maximum junction temperature. 8. Confirm that operation temperature is within the specified range described in the product specification. 9. ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined in this document. Precaution for Mounting / Circuit board design 1. When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect product performance and reliability. 2. In principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must be used on a through hole mount products. If the flow soldering method is preferred on a surface-mount products, please consult with the ROHM representative in advance. For details, please refer to ROHM Mounting specification Notice-PGA-E (c) 2015 ROHM Co., Ltd. All rights reserved. Rev.002 Datasheet Precautions Regarding Application Examples and External Circuits 1. If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of the characteristics of the Products and external components, including transient characteristics, as well as static characteristics. 2. You agree that application notes, reference designs, and associated data and information contained in this document are presented only as guidance for Products use. Therefore, in case you use such information, you are solely responsible for it and you must exercise your own independent verification and judgment in the use of such information contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses incurred by you or third parties arising from the use of such information. Precaution for Electrostatic This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not be applied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron, isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control). Precaution for Storage / Transportation 1. Product performance and soldered connections may deteriorate if the Products are stored in the places where: [a] the Products are exposed to sea winds or corrosive gases, including Cl2, H2S, NH3, SO2, and NO2 [b] the temperature or humidity exceeds those recommended by ROHM [c] the Products are exposed to direct sunshine or condensation [d] the Products are exposed to high Electrostatic 2. Even under ROHM recommended storage condition, solderability of products out of recommended storage time period may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is exceeding the recommended storage time period. 3. Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads may occur due to excessive stress applied when dropping of a carton. 4. Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products of which storage time is exceeding the recommended storage time period. Precaution for Product Label QR code printed on ROHM Products label is for ROHM's internal use only. Precaution for Disposition When disposing Products please dispose them properly using an authorized industry waste company. Precaution for Foreign Exchange and Foreign Trade act Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign trade act, please consult with ROHM in case of export. Precaution Regarding Intellectual Property Rights 1. All information and data including but not limited to application example contained in this document is for reference only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any other rights of any third party regarding such information or data. 2. ROHM shall not have any obligations where the claims, actions or demands arising from the combination of the Products with other articles such as components, circuits, systems or external equipment (including software). 3. No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to manufacture or sell products containing the Products, subject to the terms and conditions herein. Other Precaution 1. This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM. 2. The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior written consent of ROHM. 3. In no event shall you use in any way whatsoever the Products and the related technical information contained in the Products or this document for any military purposes, including but not limited to, the development of mass-destruction weapons. 4. The proper names of companies or products described in this document are trademarks or registered trademarks of ROHM, its affiliated companies or third parties. Notice-PGA-E (c) 2015 ROHM Co., Ltd. All rights reserved. Rev.002 Datasheet General Precaution 1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents. ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny ROHM's Products against warning, caution or note contained in this document. 2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior notice. Before purchasing or using ROHM's Products, please confirm the la test information with a ROHM sale s representative. 3. The information contained in this doc ument is provi ded on an "as is" basis and ROHM does not warrant that all information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or concerning such information. Notice - WE (c) 2015 ROHM Co., Ltd. All rights reserved. Rev.001 Datasheet bd3550hfn - Web Page Buy Distribution Inventory Part Number Package Unit Quantity Minimum Package Quantity Packing Type Constitution Materials List RoHS bd3550hfn HSON8 3000 3000 Taping inquiry Yes