BD9S231NUX-CE2

Datasheet 2.7 V to 5.5 V Input, 2 A Single Synchronous Buck DC/DC Converter for Automotive BD9S231NUX-C General Description Key Specifications BD9S231NUX-C is a synchronous buck DC/DC Converter with built-in low On Resistance power MOSFETs. It is capable of providing current up to 2 A. Small inductor is applicable due to high switching frequency of 2.2 MHz. It is a current mode control DC/DC Converter and features high-speed transient response. It has a built-in phase compensation circuit. Applications can be created with a few external components. ◼ ◼ ◼ ◼ ◼ ◼ ◼ ◼ Package Features ◼ ◼ ◼ ◼ ◼ ◼ ◼ ◼ ◼ Input Voltage: 2.7 V to 5.5 V Output Voltage Setting: 0.8 V to VIN Output Current: 2 A (Max) Switching Frequency: 2.2 MHz (Typ) High Side FET ON Resistance: 150 mΩ (Typ) Low Side FET ON Resistance: 95 mΩ (Typ) Shutdown Circuit Current: 0 μA (Typ) Operating Temperature: -40 °C to +125 °C W (Typ) x D (Typ) x H (Max) 2.0 mm x 2.0 mm x 0.6 mm VSON008X2020 AEC-Q100 Qualified (Note 1) Single Synchronous Buck DC/DC Converter Adjustable Soft Start Function Power Good Output Input Under Voltage Lockout Protection (UVLO) Short Circuit Protection (SCP) Output Over Voltage Protection (OVP) Over Current Protection (OCP) Thermal Shutdown Protection (TSD) (Note 1) Grade 1 Applications ◼ ◼ Automotive Equipment Other Electronic Equipment Typical Application Circuit VIN VIN PGD EN SW CIN1 VEN VOUT L1 COUT1 SS COUT2 R1 GND FB R2 〇Product structure : Silicon integrated circuit www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 14 • 001 〇This product has no designed protection against radioactive rays 1/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Pin Configuration SW 1 8 GND SW 2 7 VIN EXP-PAD SS 3 6 EN FB 4 5 PGD (TOP VIEW) Pin Descriptions Pin No. Pin Name Function 1, 2 SW Switch pin. These pins are connected to the drain of the High Side FET and the Low Side FET. 3 SS 4 FB 5 PGD Power Good pin, an open drain output. It is need to be pulled up to the power supply with a resistor. See Function Explanations 2. Power Good Function for setting the resistance. 6 EN Enable pin of the device. Turning this pin Low forces the device to enter the shutdown mode. Turning this pin High makes the device to start up. 7 VIN Power supply pin. Connecting a 10 µF (Typ) ceramic capacitor is recommended. The detail of a selection is described in Selection of Components Externally Connected 3. Selection of Input Capacitor. 8 GND Ground pin. - EXP-PAD Pin for setting the soft start time. The rise time of the output voltage can be specified by connecting a capacitor to this pin. See Selection of Components Externally Connected 5. Selection of Soft Start Capacitor for how to calculate the capacitance. VOUT feedback pin. Connect output voltage divider to this pin to set the output voltage. See Selection of Components Externally Connected 2. Selection of Output Voltage Setting on how to compute for the resistor values. A backside heat dissipation pad. Connecting to the internal PCB ground plane by using via provides excellent heat dissipation characteristics. www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 2/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Block Diagram EN 6 VREF 3 Soft Start SS VIN Slope Error Amplifier 7 PWM Comparator FB R 4 S OCP Q Driver Logic SW 1 VOUT OSC VIN 2 UVLO SCP OVP GND Power Good 8 TSD 5 PGD www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 3/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Description of Blocks 1. VREF The VREF block generates the internal reference voltage. 2. Soft Start The Soft Start circuit slows down the rise of output voltage during startup, which allows the prevention of output voltage overshoot. The soft start time of the output voltage can be specified by connecting a capacitor to the SS pin. See Selection of Components Externally Connected 5. Selection of Soft Start Capacitor for how to calculate the capacitance. A built-in soft start function is provided the soft start with Soft Start Time tSS (Electrical Characteristics) when the SS pin is open. 3. Error Amplifier The Error Amplifier block is an error amplifier and its inputs are the reference voltage and the FB pin voltage. 4. PWM Comparator The PWM Comparator block compares the output voltage of the Error Amplifier and the Slope signal to determine the output switching pulse duty. 5. OSC (Oscillator) This block generates the oscillating frequency. 6. Driver Logic This block controls switching operation and various protection functions. 7. PGD (Power Good) When the FB pin voltage reaches 0.8 V (Typ) within ±7 %, the built-in Nch MOSFET turns OFF and the PGD output turns high. There is a 3 % hysteresis on the threshold voltage, so the PGD output turns low when the FB pin voltage reaches outside ±10 % of 0.8 V (Typ). This function is enabled after soft start is completed, the time is tSS (Electrical Characteristics) when the SS pin is open, and tSS_EXT (Selection of Components Externally Connected 5. Selection of Soft Start Capacitor) when it is connected to the capacitance. 8. UVLO (Under Voltage Lockout) The UVLO block is for under voltage lockout protection. It shuts down the device when the VIN falls to 2.45 V (Typ) or less. The threshold voltage has a hysteresis of 100 mV (Typ). 9. SCP (Short Circuit Protection) This is the short circuit protection circuit. After soft start is judged to be completed, if the FB pin voltage falls to 0.56 V (Typ) or less and remain in that state for 1 ms (Typ), output MOSFETs turn OFF for 14 ms (Typ) and then restart the operation. 10. OVP (Over Voltage Protection) This is the output over voltage protection circuit. When the FB pin voltage becomes 0.88 V (Typ) or more, it turns the output MOSFETs OFF. After output voltage falls 0.856 V (Typ) or less, the output MOSFETs return to normal operation. 11. TSD (Thermal Shutdown) This is the thermal shutdown circuit. It shuts down the device when the junction temperature (Tj) reaches to 175 °C (Typ) or more. When the Tj falls below the TSD threshold, the circuits are automatically restored to normal operation with hysteresis of 25 °C (Typ). 12. OCP (Over Current Protection) The Over Current Protection function operates by limiting the current that flows through High Side FET at each cycle of the switching frequency. www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 4/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Absolute Maximum Ratings Parameter Symbol Rating Unit VIN -0.3 to +7.0 V Input Voltage EN Voltage VEN -0.3 to VIN V PGD Voltage VPGD -0.3 to +7.0 V VFB, VSS -0.3 to VIN V Tjmax 150 °C Tstg -55 to +150 °C FB, SS Voltage Maximum Junction Temperature Storage Temperature Range Caution 1: 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. Caution 2: Should by any chance the maximum junction temperature rating be exceeded the rise in temperature of the chip may result in deterioration of the properties of the chip. In case of exceeding this absolute maximum rating, design a PCB with thermal resistance taken into consideration by increasing board size and copper area so as not to exceed the maximum junction temperature rating. Thermal Resistance (Note 1) Parameter Symbol Thermal Resistance (Typ) Unit 1s (Note 3) 2s2p (Note 4) θJA 181.90 47.90 °C/W ΨJT 20.00 7.00 °C/W VSON008X2020 Junction to Ambient Junction to Top Characterization Parameter (Note 2) (Note 1) Based on JESD51-2A(Still-Air), using a BD9S231NUX-C Chip. (Note 2) The thermal characterization parameter to report the difference between junction temperature and the temperature at the top center of the outside surface of the component package. (Note 3) Using a PCB board based on JESD51-3. (Note 4) Using a PCB board based on JESD51-5, 7. Layer Number of Measurement Board Single Material Board Size FR-4 114.3 mm x 76.2 mm x 1.57 mmt Top Copper Pattern Thickness Footprints and Traces 70 μm Layer Number of Measurement Board 4 Layers Material Board Size FR-4 114.3 mm x 76.2 mm x 1.6 mmt Top Thermal Via (Note 5) Pitch Diameter 1.20 mm Φ0.30 mm 2 Internal Layers Bottom Copper Pattern Thickness Copper Pattern Thickness Copper Pattern Thickness Footprints and Traces 70 μm 74.2 mm x 74.2 mm 35 μm 74.2 mm x 74.2 mm 70 μm (Note 5) This thermal via connects with the copper pattern of all layers. Recommended Operating Conditions Parameter Symbol Min Max Unit VIN 2.7 5.5 V Operating Temperature Ta -40 +125 °C Output Current IOUT - 2 A (Note 1) VIN V - 80 ns Input Voltage Output Voltage Setting VOUT SW Minimum ON Time tON_MIN 0.8 (Note 1) Although the output voltage is configurable at 0.8 V and higher, it may be limited by the SW min ON pulse width. For the configurable range, Refer to the Output Voltage Setting on page 16 in Selection of Components Externally Connected. www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 5/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Electrical Characteristics (Unless otherwise specified Ta = Tj = -40 °C to +125 °C, VIN = 5.0 V, VEN = 5.0 V, the typical value is defined at Ta = Tj = +25 °C) Parameter Symbol Min Typ Max Unit Shutdown Circuit Current ISDN - 0 10 µA Circuit Current ICC 250 400 550 µA VUVLO1 VUVLO2 VUVLO-HYS 2.30 2.40 50 2.45 2.55 100 2.60 2.70 125 V V mV VENH VENL IEN 1.0 GND 2.0 5.0 VIN 0.5 8.0 V V µA VFB IFB 0.788 - 0.800 0 0.812 0.2 V µA 0.5 1.0 2.0 ms 0.6 1.2 2.4 ms ISS -1.4 -1.0 -0.6 µA fSW 2.0 2.2 2.4 MHz VFB x 0.87 VFB x 0.90 VFB x 1.07 VFB x 1.04 30 0.03 VFB x 0.90 VFB x 0.93 VFB x 1.10 VFB x 1.07 0 60 0.06 VFB x 0.93 VFB x 0.96 VFB x 1.13 VFB x 1.10 2.0 120 0.12 80 90 55 60 150 175 95 100 Conditions VIN UVLO Detection Voltage UVLO Release Voltage UVLO Hysteresis Voltage VEN = 0 V, Ta = 25 °C IOUT = 0 mA Non-switching, Ta = 25 °C VIN Falling VIN Rising ENABLE EN Input Voltage High EN Input Voltage Low EN Input Current VEN = 5.0 V, Ta = 25 °C Reference Voltage FB Pin Voltage FB Input Current (Note 1) VFB = 0.8 V, Ta = 25 °C Soft Start Soft Start Time SS Charge Current tSS VIN = 5.0 V, The SS Pin OPEN VIN = 3.3 V, The SS Pin OPEN Switching Frequency Switching Frequency Power Good PGD Falling (Fault) Voltage VPGDTH_FF PGD Rising (Good) Voltage VPGDTH_RG PGD Rising (Fault) Voltage VPGDTH_RF PGD Falling (Good) Voltage VPGDTH_FG PGD Output Leakage Current PGD FET ON Resistance PGD Output Low Level Voltage ILEAKPGD RPGD VPGDL V VFB Falling V VFB Rising V VFB Rising V VFB Falling µA Ω V VPGD = 5.0 V, Ta = 25 °C 250 280 150 160 mΩ mΩ mΩ mΩ VIN = 5.0 V VIN = 3.3 V VIN = 5.0 V VIN = 3.3 V VIN = 5.5 V, VSW = 0 V, Ta = 25 °C VIN = 5.5 V, VSW = 5.5 V, Ta = 25 °C IPGD = 1.0 mA Switch MOSFET High Side FET ON Resistance RONH Low Side FET ON Resistance RONL High Side FET Leakage Current ILEAKSWH - 0 5.0 μA Low Side FET Leakage Current ILEAKSWL - 0 5.0 μA IOCP 2.50 3.00 3.50 A VSCP 0.48 0.56 0.64 V VFB Falling VOVP 0.856 0.880 0.904 V VFB Rising SW Current of Over Current Protection (Note 2) SCP, OVP Short Circuit Protection Detection Voltage Output Over Voltage Protection Detection Voltage (Note 1) It is tested in a proprietary test mode that connects FB pin to the output of the error amplifier. (Note 2) This is design value. Not production tested. www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 6/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Typical Performance Curves Unless otherwise specified VIN = VEN 550 VEN = 0 V 9 500 8 7 Circuit Current : ICC[µA] Shutdown Circuit Current : ISDN[µA] 10 6 5 4 VIN = 5.0 V 3 VIN = 3.3 V 2 VIN = 5.0 V 450 400 350 300 1 VIN = 3.3 V 0 -50 -25 0 25 50 75 100 250 125 -50 0 25 50 75 100 125 Temperature[°C] Temperature[°C] Figure 1. Shutdown Circuit Current vs Temperature Figure 2. Circuit Current vs Temperature 2.40 0.812 2.35 VIN = 5.0 V 0.808 2.30 FB Pin Voltage : VFB[V] Switching Frequency : fSW [MHz] -25 2.25 2.20 2.15 VIN = 3.3 V 2.10 VIN = 5.0 V 0.804 0.800 0.796 VIN = 3.3 V 0.792 2.05 2.00 0.788 -50 -25 0 25 50 75 100 125 -50 0 25 50 75 100 125 Temperature[°C] Temperature[°C] Figure 3. Switching Frequency vs Temperature www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 -25 7/39 Figure 4. FB Pin Voltage vs Temperature TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Typical Performance Curves – continued -0.60 2.0 CSS = OPEN 1.8 -0.70 VIN = 3.3 V SS Charge Current : ISS[µA] Soft Start Time : tSS[ms] 1.6 1.4 1.2 1.0 0.8 0.6 VIN = 5.0 V 0.4 -0.80 VIN = 3.3 V -0.90 -1.00 -1.10 VIN = 5.0 V -1.20 -1.30 0.2 0.0 -1.40 -50 -25 0 25 50 75 100 125 -50 -25 0 Temperature[°C] 50 75 100 125 Temperature[°C] Figure 5. Soft Start Time vs Temperature Figure 6. SS Charge Current vs Temperature 280 160 Low Side FET ON Resistance : RONL[mΩ] High Side FET ON Resistance : RONH[mΩ] 25 260 240 220 VIN = 3.3 V 200 180 160 140 VIN = 5.0 V 120 100 150 140 130 VIN = 3.3 V 120 110 100 90 VIN = 5.0 V 80 70 60 50 80 -50 -25 0 25 50 75 100 125 -25 0 25 50 75 100 125 Temperature[°C] Temperature[°C] Figure 7. High Side FET ON Resistance vs Temperature www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 -50 8/39 Figure 8. Low Side FET ON Resistance vs Temperature TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Typical Performance Curves – continued 5.0 VEN = 0 V Low Side FET Leakage Current : ILEAKSWL [µA] High Side FET Leakage Current : ILEAKSWH [µA] 5.0 4.0 3.0 2.0 VIN = 5.0 V VIN = 3.3 V 1.0 0.0 -50 -25 0 25 50 75 100 125 VEN = 0 V 4.0 3.0 2.0 VIN = 5.0 V VIN = 3.3 V 1.0 0.0 -50 -25 0 25 Temperature [°C] 75 100 125 Temperature [°C] Figure 9. High Side FET Leakage Current vs Temperature Figure 10. Low Side FET Leakage Current vs Temperature 120 0.90 VIN = 5.0 V VIN = 5.0 V PGD FET ON Resistance : RPGD[Ω] PGD Threshold Voltage [V] 50 0.86 Falling Good VPGDTH_FG 0.82 0.78 Falling Fault VPGDTH_FF Rising Fault VPGDTH_RF Rising Good VPGDTH_RG 0.74 110 100 90 80 70 60 50 40 30 0.70 -50 -25 0 25 50 75 100 125 -25 0 25 50 75 100 125 Temperature[°C] Temperature[°C] Figure 11. PGD Threshold Voltage vs Temperature www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 -50 9/39 Figure 12. PGD FET ON Resistance vs Temperature TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Typical Performance Curves – continued 1.0 2.70 VIN = 5.0 V EN Input Voltage : VEN[V] UVLO Voltage : VUVLO[V] 2.65 Release 2.60 2.55 2.50 2.45 2.40 Detection 0.9 High 0.8 0.7 Low 0.6 2.35 2.30 0.5 -50 -25 0 25 50 75 Temperature[°C] 100 125 -50 Figure 13. UVLO Detection Voltage vs Temperature 0 25 50 75 Temperature[°C] 100 125 Figure 14. EN Input Voltage vs Temperature 10 SW Current of Over Current Protection : IOCP[A] 3.5 9 8 EN Input Current : IEN[µA] -25 7 6 VEN = 5.0 V 5 4 3 2 VEN = 3.3 V 1 0 -50 -25 0 25 50 75 100 125 Temperature[°C] 3.3 3.2 3.1 3.0 2.9 2.8 2.7 2.6 2.5 -50 -25 0 25 50 75 100 125 Temperature[°C] Figure 15. EN Input Current vs Temperature www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 VIN = 5.0 V 3.4 Figure 16. SW Current of Over Current Protection vs Temperature 10/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Short Circuit Protection Detection Voltage : VSCP[V] 0.64 VIN = 5.0 V 0.62 Release 0.60 0.58 0.56 0.54 Detection 0.52 0.50 0.48 -50 -25 0 25 50 75 100 125 Temperature[°C] Figure 17. Short Circuit Protection Detection Voltage vs Temperature www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 11/39 Output Over Voltage Protection Detection Voltage : VOVP[V] Typical Performance Curves – continued 0.9 VIN = 5.0 V Detection 0.89 0.88 0.87 0.86 0.85 Release 0.84 0.83 -50 -25 0 25 50 75 100 125 Temperature[°C] Figure 18. Output Over Voltage Protection Detection Voltage vs Temperature TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Function Explanations 1. Enable Control The device shutdown can be controlled by the voltage applied to the EN pin. When VEN becomes 1.0 V or more, the internal circuit is activated and the device starts up with soft start. When VEN becomes 0.5 V or less, the device is shutdown. The PGD output is enabled after soft start is completed. VIN 0 t VEN VENH VENL 0 t VOUT VOUT × 0.93 (Typ) 0 t tSS PGD tWAIT 200 µs (Typ) 0 t Figure 19. Enable ON/OFF Timing Chart (The SS Pin OPEN) 2. Power Good Output When the FB pin voltage reaches 0.8 V (Typ) within ±7 %, the PGD pin open drain MOSFET turns OFF and the output turns high. There is a 3 % hysteresis on the threshold voltage, so when the FB pin voltage reaches outside ±10 % of 0.8 V (Typ), the PGD pin open drain MOSFET turns ON and the PGD pin is pulled down with impedance of 60 Ω (Typ). This function is enabled after soft start is completed, the time is tSS (Electrical Characteristics) when the SS pin is open, and tSS_EXT (Selection of Components Externally Connected 5. Selection of Soft Start Capacitor) when it is connected to the capacitance. It is recommended to use a pull-up resistor of 2 kΩ to 100 kΩ for the power source. +10 % (Typ) +7 % (Typ) VFB -7 % (Typ) -10 % (Typ) PGD Figure 20. Power Good Timing Chart www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 12/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C 2. Power Good Function – continue EN Pin UVLO 1.0 V or more Protection (OCP, TSD) (Note 1) Power Good Function Undetected Enable Detected Unenable Release Detection 0.5 V or less Power Good Output High / Low Low - (Note 1) When the FB pin voltage reaches outside ±10 % of 0.8 V (TYP) by detected protection (OCP, TSD), the power good output terns low. 3. Pre-bias Function The device can start up without sinking a large current from output even if it is in the state of pre-biased. For example, if the device enabled during pre-biased condition, integrated MOSFETs keep OFF until internal SS voltage exceeds FB voltage by more than 40 mV (Typ). After that, the device starts switching and the output voltage increases with soft start. The PGD output is enabled after soft start is completed. VEN Soft Start VOUT 0V 40 mV (Typ) FB Internal SS Output MOSFETs OFF SW PGD Figure 21. Pre-bias Start Up Timing Chart 4. 100 % ON Duty Cycle When the input voltage comes close to the setting output voltage, the High Side FET is turned on 100 % for one or more cycle in order to maintain the output voltage. With further decreasing the input voltage, the High Side FET is turned on completely. The minimum input voltage to maintain the output voltage can be represented by following equation. 𝑉𝐼𝑁(𝑀𝑖𝑛) = 𝑉𝑂𝑈𝑇 + 𝐼𝑂𝑈𝑇(𝑀𝑎𝑥) × (𝑅𝑂𝑁𝐻(𝑀𝑎𝑥) + 𝑅𝐿(𝑀𝑎𝑥) ) [V] where 𝑉𝑂𝑈𝑇 𝐼𝑂𝑈𝑇(𝑀𝑎𝑥) 𝑅𝑂𝑁𝐻(𝑀𝑎𝑥) 𝑅𝐿(𝑀𝑎𝑥) is the output voltage is the maximum output current is the High Side FET ON Resistance (Electrical Characteristics) is the DC resistance of the inductor www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 13/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Protection 1. Short Circuit Protection (SCP) The Short Circuit Protection block compares the FB pin voltage with the internal reference voltage VREF. When the FB pin voltage has fallen to 0.56 V (Typ) or less and remained there for 1 ms (Typ), SCP stops the operation for 14 ms (Typ) and subsequently initiates a restart. This protection circuit is effective in preventing damage due to sudden and unexpected incidents. However, the device should not be used in applications characterized by continuous operation of the protection circuit (e.g. when a load that significantly exceeds the output current capability of the chip is connected at all times). EN Pin Short Circuit Protection FB Pin ≤ 0.56 V (Typ) 1.0 V or more ON Enabled ≥ 0.60 V (Typ) 0.5 V or less Short Circuit Protection Operation - OFF Disabled OFF tSS VOUT 1 ms (Typ) 1 ms (Typ) 0.8 V FB VSCP : 0.56 V (Typ) SCP OFF : 0.60 V (Typ) SW LOW IOCP Inductor Current (Output Load Current) Internal HICCUP Delay Signal 14 ms (Typ) SCP Reset Figure 22. SCP Timing Chart 2. Over Current Protection (OCP) The Over Current Protection function operates by limiting the current that flows through High Side FET at each cycle of the switching frequency. This protection circuit is effective in preventing damage due to sudden and unexpected incidents. However, the device should not be used in applications characterized by continuous operation of the protection circuit (e.g. when a load that significantly exceeds the output current capability of the chip is connected at all times). www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 14/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Protection – continued 3. Under Voltage Lockout Protection (UVLO) It shuts down the device when the VIN pin falls to 2.45 V (Typ) or less. The threshold voltage has a hysteresis of 100 mV (Typ). VIN ( = VEN) VUVLO-HYS 100 mV (Typ) VUVLO2 : 2.55 V (Typ) VUVLO1 : 2.45 V (Typ) 0V tWAIT 200 µs (Typ) VOUT tSS SW Normal operation UVLO Normal operation Figure 23. UVLO Timing Chart 4. Thermal Shutdown (TSD) This is the thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always be within the IC’s maximum junction temperature rating. However, if the rating is exceeded for a continued period and the junction temperature (Tj) rises to 175 °C (Typ), the TSD circuit activates and the output MOSFETs turn OFF. 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. 5. Over Voltage Protection (OVP) The device incorporates an over voltage protection circuit to minimize the output voltage overshoot when recovering from strong load transients or output fault conditions. If the FB pin voltage becomes over or equal to 0.88 V (Typ), which is Output Over Voltage Protection Detection Voltage, the MOSFETs on the output stage are turned OFF to prevent the increase in the output voltage. After the detection, the switching operation resumes if the output decreases, the over voltage state is released, and FB pin voltage reaches 0.8 V (Typ). Output Over Voltage Protection Detection Voltage and release voltage have a hysteresis of 3 %. VOUT VOVP : 0.88 V (Typ) hys : 3 % FB SW Internal OVP Signal Figure 24. OVP Timing Chart www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 15/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Selection of Components Externally Connected Contact us if not use the recommended constant in this section. Necessary parameters in designing the power supply are as follows: Parameter Input Voltage Output Voltage Switching Frequency Output Ripple Current Output Capacitor Soft Start Time Maximum Output Current Table 1. Application Specification Symbol VIN VOUT fSW ΔIL COUT tSS IOUTMAX Example Value 5.0 V 1.15 V (Typ) 2.2 MHz (Typ) 0.40 A 44 μF 8.5 ms (Typ) 2.0 A Application Example R3 VIN VIN PGD EN SW PGD CIN1 VEN VOUT L1 SS C1 GND R100 COUT1 R1 COUT2 FB CSS R2 Figure 25. Application Circuit 1. Switching Frequency The switching frequency fSW is fixed at 2.2 MHz (Typ) inside the IC. 2. Selection of Output Voltage Setting The output voltage value can be set by the feedback resistance ratio. 𝑉𝑂𝑈𝑇 = VOUT R1 ※ FB R2 0.8 V(Typ) 𝑅1 +𝑅2 𝑅2 SW Minimum ON Time that BD9S231NUX-C can output stably in the entire load range is 80 ns. Use this value to calculate the input and output conditions that satisfy the following equation. 80 [ns] ≤ ※ × 0.8 [V] 𝑉𝑂𝑈𝑇 𝑉𝐼𝑁 × 𝑓𝑆𝑊 Use R1 and R2 under the following the condition in order to prevent the output from rising due to leakage current. Figure 26. Feedback Resistor Circuit R1 + R2 ≤ 95 [kΩ] www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 16/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Selection of Components Externally Connected – continued 3. Selection of Input Capacitor Use ceramic type capacitor for the input capacitor CIN1. CIN1 is used to suppress the input ripple noise and this capacitor is effective by being placed as close as possible to the VIN pin. Set the capacitor value for C IN1 so that it does not fall to 4.7 μF against the capacitor value variances, temperature characteristics, DC bias characteristics, aging characteristics, and etc. Use components which are comparatively same with the components used in “Application Example” on page 19. Moreover, factors like the PCB layout and the position of the capacitor may lead to IC malfunction. Please refer to “PCB layout Design” on page 31 and 32. In addition, the capacitor with value 0.1 μF can be added to suppress the high frequency noise as an option. 4. Selection of Output LC Filter In order to supply a continuous current to the load, the DC/DC converter requires an LC filter for smoothing the output voltage. Use the inductor with value 1.0 μH to 1.5 μH. VIN Inductor Saturation Current > IOUTMAX + ∆IL/2 ∆IL L1 VOUT Driver Maximum Output Current I OUTMAX COUT t Figure 27. Waveform of Current through Inductor Figure 28. Output LC Filter Circuit Inductor ripple current ΔIL can be represented by the following equation. ∆𝐼𝐿 = 𝑉𝑂𝑈𝑇 × (𝑉𝐼𝑁 − 𝑉𝑂𝑈𝑇 ) × 𝑉 1 𝐼𝑁 ×𝑓𝑆𝑊 ×𝐿1 = 403 [mA] where 𝑉𝐼𝑁 𝑉𝑂𝑈𝑇 𝐿1 𝑓𝑆𝑊 is the 5.0 V is the 1.15 V is the 1.0 µH is the 2.2 MHz (Switching Frequency) The rated current of the inductor must be larger than the sum of the maximum output current and 1/2 of the inductor ripple current ΔIL. Use ceramic type capacitor for the output capacitor COUT. The capacitance value of COUT is recommended in the range between 44 μF and 94 μF. COUT affects the output ripple voltage characteristics. COUT must satisfy the required ripple voltage characteristics. The output ripple voltage can be represented by the following equation. ∆𝑉𝑅𝑃𝐿 = ∆𝐼𝐿 × (𝑅𝐸𝑆𝑅 + 8×𝐶 1 𝑂𝑈𝑇 ×𝑓𝑆𝑊 ) [V] Where 𝑅𝐸𝑆𝑅 is the Equivalent Series Resistance (ESR) of the output capacitor. The output ripple voltage ΔVRPL can be represented by the following equation. 1 ∆𝑉𝑅𝑃𝐿 = 0.403 𝐴 × (10 𝑚𝛺 + 8×44 𝜇𝐹×2.2 𝑀𝐻𝑧) = 5.55 [mV] where 𝐶𝑂𝑈𝑇 𝑅𝐸𝑆𝑅 is the 44 µF is the 10 mΩ www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 17/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C 4. Selection of Output LC Filter – continued Stable transient response and the loop is dependent to COUT. Actually, characteristics vary depending on PCB layout, arrangement of wiring, kinds of parts used and use conditions (temperature, etc.). Be sure to check stability and responsiveness with the actual application. 5. Selection of Soft Start Capacitor Turning the EN pin signal high activates the soft start function. This causes the output voltage to rise gradually while the current at startup is placed under control. This allows the prevention of output voltage overshoot and inrush current. The rise time tSS_EXT depends on the value of the capacitor connected to the SS pin. The capacitance value should be set in the range between 4700 pF and 0.082 μF. VEN 𝑡𝑆𝑆_𝐸𝑋𝑇 = (𝐶𝑆𝑆 ×0.8) 𝐼𝑆𝑆 + 𝑡𝑂𝐹𝐹𝑆𝐸𝑇 [s] VENH VENL 𝑡𝑂𝐹𝐹𝑆𝐸𝑇 = (𝐶𝑆𝑆 ×0.04) 𝐼𝑆𝑆 0 + 150 × 10−6 [s] t VOUT where 𝑡𝑆𝑆_𝐸𝑋𝑇 𝑡𝑂𝐹𝐹𝑆𝐸𝑇 𝐶𝑆𝑆 𝐼𝑆𝑆 is the Soft Start Time is the Internal Delay Time is the Capacitor connected to the SS pin 0 t tSS_EXT is the SS Charge Current 1.0 µA (Typ) tOFFSET With CSS = 0.01 μF Figure 29. Soft Start Timing Chart 𝑡𝑆𝑆_𝐸𝑋𝑇 = (0.01 𝜇𝐹×0.8) 1.0 𝜇𝐴 + (0.01 𝜇𝐹×0.04) 1.0 𝜇𝐴 + 150 × 10 −6 = 0.00855 = 8.55 [ms] Turning the EN pin High without connecting capacitor to the SS pin and keeping the SS pin either OPEN condition or 10 kΩ to 100 kΩ pull up condition to power source, the output rises in 1.0 ms (Typ). Recommended Parts Manufacturer List Shown below is the list of the recommended parts manufacturers for reference. Table 2. recommended parts manufacturers Type Manufacturer Ceramic capacitor Murata www.murata.com Ceramic capacitor TDK product.tdk.com Inductor Coilcraft www.coilcraft.com Inductor Cyntec www.cyntec.com Inductor Murata www.murata.com Inductor Sumida www.sumida.com Inductor TDK product.tdk.com Resistor ROHM www.rohm.com www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 18/39 URL TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Application Example 1 Table 3. Specification Example 1 Parameter Product Name Input Voltage Output Voltage Soft Start Time Maximum Output Current Operation Temperature Range Symbol Example Value IC BD9S231NUX-C VIN 5.0 V, 3.3 V VOUT 1.0 V tSS 1.0 ms (Typ) IOUTMAX 2.0 A Ta -40 °C to +125 °C R3 VIN VIN PGD EN SW PGD CIN1 VEN VOUT L1 SS C1 GND R100 COUT1 R1 COUT2 FB CSS R2 Figure 30. Reference Circuit 1 Parameters Table 4. Parts List 1 Part Name (Series) No Package Type Manufacturer L1 COUT1 2520 1.0 μH TFM252012ALMA1R0M Inductor TDK 3216 22 μF, X7R, 6.3 V GCM31CR70J226K Ceramic Capacitor Murata COUT2 3216 22 μF, X7R, 6.3 V GCM31CR70J226K Ceramic Capacitor Murata CIN1 2012 10 μF, X7R, 10 V GCM21BR71A106K Ceramic Capacitor Murata R100 - SHORT - - - R1 1005 7.5 kΩ, 1 %, 1/16 W MCR01MZPF7501 Chip Resistor ROHM R2 1005 30 kΩ, 1 %, 1/16 W MCR01MZPF3002 Chip Resistor ROHM R3 1005 100 kΩ, 1 %, 1/16 W MCR01MZPF1003 Chip Resistor ROHM CSS - - - - - C1 - - - - - www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 19/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Characteristic Data (Application Examples 1) VIN = VEN, Ta = 25 °C 100 80 180 VIN = 5.0 V 90 60 135 40 90 20 45 0 0 60 VIN = 5.0 V 50 VIN = 3.3 V 40 Gain[dB] Efficiency [%] 70 -20 -45 Phase[deg] 80 30 Gain -40 20 -90 Phase -60 10 0 0.0 0.5 1.0 1.5 Output Current [A] -135 -80 2.0 1 Figure 31. Efficiency vs Output Current 10 100 Frequency [kHz] Figure 32. Gain vs Frequency (IOUT = 2 A) Time: 20 μs/div Time: 500 ns/div VOUT: 50 mV/div VOUT: 20 mV/div IOUT: 500 mA/div IOUT: 1 A/div Figure 33. Load Transient Response (IOUT = 0 A ↔ 1 A) www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 -180 1000 Figure 34. Output Ripple Voltage (IOUT = 2 A) 20/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Application Example 2 Table 5. Specification Example 2 Parameter Product Name Input Voltage Output Voltage Soft Start Time Maximum Output Current Operation Temperature Range Symbol Example Value IC BD9S231NUX-C VIN 5.0 V, 3.3 V VOUT 1.15 V tSS 1.0 ms (Typ) IOUTMAX 2.0 A Ta -40 °C to +125 °C R3 VIN VIN PGD EN SW PGD CIN1 VEN VOUT L1 SS C1 GND R100 COUT1 R1 COUT2 FB CSS R2 Figure 35. Reference Circuit 2 Table 6. Parts List 2 No Package Parameters Part Name (Series) L1 COUT1 Type Manufacturer 2520 1.0 μH TFM252012ALMA1R0M Inductor TDK 3216 22 μF, X7R, 6.3 V GCM31CR70J226K Ceramic Capacitor Murata COUT2 3216 22 μF, X7R, 6.3 V GCM31CR70J226K Ceramic Capacitor Murata CIN1 2012 10 μF, X7R, 10 V GCM21BR71A106K Ceramic Capacitor Murata R100 - SHORT - - - R1 1005 27 kΩ, 1 %, 1/16 W MCR01MZPF2702 Chip Resistor ROHM R2 1005 62 kΩ, 1 %, 1/16 W MCR01MZPF6202 Chip Resistor ROHM R3 1005 100 kΩ, 1 %, 1/16 W MCR01MZPF1003 Chip Resistor ROHM CSS - - - - - C1 - - - - - www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 21/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Characteristic Data (Application Examples 2) VIN = VEN, Ta = 25 °C 80 100 180 VIN = 5.0 V 90 60 135 80 40 90 20 45 0 0 VIN = 5.0 V 50 VIN = 3.3 V 40 -20 30 -45 Gain -40 Phase[deg] 60 Gain[dB] Efficiency [%] 70 -90 Phase 20 -60 -135 10 -80 0 0.0 0.5 1.0 1.5 Output Current [A] 1 2.0 Figure 36. Efficiency vs Output Current 10 100 Frequency [kHz] Figure 37. Gain vs Frequency (IOUT = 2 A) Time: 20 μs/div Time: 500 ns/div VOUT: 50 mV/div VOUT: 20 mV/div IOUT: 500 mA/div IOUT: 1 A/div Figure 38. Load Transient Response (IOUT = 0 A ↔ 1 A) www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 -180 1000 Figure 39. Output Ripple Voltage (IOUT = 2 A) 22/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Application Example 3 Table 7. Specification Example 3 Parameter Product Name Input Voltage Output Voltage Soft Start Time Maximum Output Current Operation Temperature Range Symbol Example Value IC BD9S231NUX-C VIN 5.0 V, 3.3 V VOUT 1.15 V tSS 1.0 ms (Typ) IOUTMAX 2.0 A Ta -40 °C to +125 °C R3 VIN VIN PGD EN SW PGD CIN1 VEN VOUT L1 SS C1 GND R100 COUT1 R1 COUT2 FB CSS R2 Figure 40. Reference Circuit 3 Table 8. Parts List 3 No Package Parameters Part Name (Series) L1 COUT1 Type Manufacturer 2520 1.0 μH TFM252012ALMA1R0M Inductor TDK 3225 47 μF, X7R, 6.3 V GCM32ER70J476K Ceramic Capacitor Murata COUT2 3225 47 μF, X7R, 6.3 V GCM32ER70J476K Ceramic Capacitor Murata CIN1 2012 10 μF, X7R, 10 V GCM21BR71A106K Ceramic Capacitor Murata R100 - SHORT - - - R1 1005 27 kΩ, 1 %, 1/16 W MCR01MZPF2702 Chip Resistor ROHM R2 1005 62 kΩ, 1 %, 1/16 W MCR01MZPF6202 Chip Resistor ROHM R3 1005 100 kΩ, 1 %, 1/16 W MCR01MZPF1003 Chip Resistor ROHM CSS - - - - - C1 - - - - - www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 23/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Characteristic Data (Application Examples 3) VIN = VEN, Ta = 25 °C 80 100 180 VIN = 5.0 V 90 60 135 80 40 90 20 45 0 0 VIN = 5.0 V 50 VIN = 3.3 V 40 -20 30 -45 Gain -40 Phase[deg] 60 Gain[dB] Efficiency [%] 70 -90 Phase 20 -60 -135 10 -80 0 0.0 0.5 1.0 1.5 Output Current [A] 1 2.0 Figure 41. Efficiency vs Output Current 10 100 Frequency [kHz] Figure 42. Gain vs Frequency (IOUT = 2 A) Time: 20 μs/div Time: 500 ns/div VOUT: 50 mV/div VOUT: 20 mV/div IOUT: 500 mA/div IOUT: 1 A/div Figure 43. Load Transient Response (IOUT = 0 A ↔ 1 A) www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 -180 1000 Figure 44. Output Ripple Voltage (IOUT = 2 A) 24/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Application Example 4 Table 9. Specification Example 4 Parameter Product Name Input Voltage Output Voltage Soft Start Time Maximum Output Current Operation Temperature Range Symbol Example Value IC BD9S231NUX-C VIN 5.0 V, 3.3 V VOUT 1.2 V tSS 1.0 ms (Typ) IOUTMAX 2.0 A Ta -40 °C to +125 °C R3 VIN VIN PGD EN SW PGD CIN1 VEN VOUT L1 SS C1 GND R100 COUT1 R1 COUT2 FB CSS R2 Figure 45. Reference Circuit 4 Table 10. Parts List 4 No Package Parameters Part Name (Series) L1 COUT1 Type Manufacturer 2520 1.0 μH TFM252012ALMA1R0M Inductor TDK 3216 22 μF, X7R, 6.3 V GCM31CR70J226K Ceramic Capacitor Murata COUT2 3216 22 μF, X7R, 6.3 V GCM31CR70J226K Ceramic Capacitor Murata CIN1 2012 10 μF, X7R, 10 V GCM21BR71A106K Ceramic Capacitor Murata R100 - SHORT - - - R1 1005 10 kΩ, 1 %, 1/16 W MCR01MZPF1002 Chip Resistor ROHM R2 1005 20 kΩ, 1 %, 1/16 W MCR01MZPF2002 Chip Resistor ROHM R3 1005 100 kΩ, 1 %, 1/16 W MCR01MZPF1003 Chip Resistor ROHM CSS - - - - - C1 - - - - - www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 25/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Characteristic Data (Application Examples 4) VIN = VEN, Ta = 25 °C 80 100 180 VIN = 5.0 V 90 60 135 80 40 90 20 45 0 0 VIN = 5.0 V 50 VIN = 3.3 V 40 -20 30 -45 Gain -40 Phase[deg] 60 Gain[dB] Efficiency [%] 70 -90 Phase 20 -60 -135 10 -80 0 0.0 0.5 1.0 1.5 Output Current [A] 1 2.0 Figure 46. Efficiency vs Output Current 10 100 Frequency [kHz] Figure 47. Gain vs Frequency (IOUT = 2 A) Time: 20 μs/div Time: 500 ns/div VOUT: 50 mV/div VOUT: 20 mV/div IOUT: 500 mA/div IOUT: 1 A/div Figure 48. Load Transient Response (IOUT = 0 A ↔ 1 A) www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 -180 1000 Figure 49. Output Ripple Voltage (IOUT = 2 A) 26/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Application Example 5 Table 11. Specification Example 5 Parameter Product Name Input Voltage Output Voltage Soft Start Time Maximum Output Current Operation Temperature Range Symbol Example Value IC BD9S231NUX-C VIN 5.0 V, 3.3 V VOUT 1.5 V tSS 1.0 ms (Typ) IOUTMAX 2.0 A Ta -40 °C to +125 °C R3 VIN VIN PGD EN SW PGD CIN1 VEN VOUT L1 SS C1 GND R100 COUT1 R1 COUT2 FB CSS R2 Figure 50. Reference Circuit 5 Table 12. Parts List 5 No Package Parameters Part Name (Series) L1 COUT1 Type Manufacturer 2520 1.0 μH TFM252012ALMA1R0M Inductor TDK 3216 22 μF, X7R, 6.3 V GCM31CR70J226K Ceramic Capacitor Murata COUT2 3216 22 μF, X7R, 6.3 V GCM31CR70J226K Ceramic Capacitor Murata CIN1 2012 10 μF, X7R, 10 V GCM21BR71A106K Ceramic Capacitor Murata R100 - SHORT - - - R1 1005 16 kΩ, 1 %, 1/16 W MCR01MZPF1602 Chip Resistor ROHM R2 1005 18 kΩ, 1 %, 1/16 W MCR01MZPF1802 Chip Resistor ROHM R3 1005 100 kΩ, 1 %, 1/16 W MCR01MZPF1003 Chip Resistor ROHM CSS - - - - - C1 - - - - - www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 27/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Characteristic Data (Application Examples 5) VIN = VEN, Ta = 25 °C 80 100 180 VIN = 5.0 V 90 60 135 80 40 90 20 45 0 0 VIN = 5.0 V 50 VIN = 3.3 V 40 -20 30 -40 -45 Gain Phase[deg] 60 Gain[dB] Efficiency [%] 70 -90 Phase 20 -60 -135 10 -80 0 0.0 0.5 1.0 1.5 Output Current [A] 1 2.0 Figure 51. Efficiency vs Output Current 10 100 Frequency [kHz] Figure 52. Gain vs Frequency (IOUT = 2 A) Time: 20 μs/div Time: 500 ns/div VOUT: 50 mV/div VOUT: 20 mV/div IOUT: 500 mA/div IOUT: 1 A/div Figure 53. Load Transient Response (IOUT = 0 A ↔ 1 A) www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 -180 1000 Figure 54. Output Ripple Voltage (IOUT = 2 A) 28/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Application Example 6 Table 13. Specification Example 6 Parameter Product Name Input Voltage Output Voltage Soft Start Time Maximum Output Current Operation Temperature Range Symbol Example Value IC BD9S231NUX-C VIN 5.0 V, 3.3 V VOUT 1.8 V tSS 1.0 ms (Typ) IOUTMAX 2.0 A Ta -40 °C to +125 °C R3 VIN VIN PGD EN SW PGD CIN1 VEN VOUT L1 SS C1 GND R100 COUT1 R1 COUT2 FB CSS R2 Figure 55. Reference Circuit 6 Table 14. Parts List 6 No Package Parameters Part Name (Series) L1 COUT1 Type Manufacturer 2520 1.0 μH TFM252012ALMA1R0M Inductor TDK 3216 22 μF, X7R, 6.3 V GCM31CR70J226K Ceramic Capacitor Murata COUT2 3216 22 μF, X7R, 6.3 V GCM31CR70J226K Ceramic Capacitor Murata CIN1 2012 10 μF, X7R, 10 V GCM21BR71A106K Ceramic Capacitor Murata R100 - SHORT - - - R1 1005 30 kΩ, 1 %, 1/16 W MCR01MZPF3002 Chip Resistor ROHM R2 1005 24 kΩ, 1 %, 1/16 W MCR01MZPF2402 Chip Resistor ROHM R3 1005 100 kΩ, 1 %, 1/16 W MCR01MZPF1003 Chip Resistor ROHM CSS - - - - - C1 - - - - - www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 29/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Characteristic Data (Application Examples 6) VIN = VEN, Ta = 25 °C 80 100 180 VIN = 5.0 V 90 60 135 80 40 90 20 45 0 0 VIN = 5.0 V VIN = 3.3 V 50 40 -20 30 -40 -45 Gain Phase[deg] 60 Gain[dB] Efficiency [%] 70 -90 Phase 20 -60 -135 10 -80 0 0.0 0.5 1.0 1.5 Output Current [A] 1 2.0 Figure 56. Efficiency vs Output Current 10 100 Frequency [kHz] Figure 57. Gain vs Frequency (IOUT = 2 A) Time: 20 μs/div Time: 500 ns/div VOUT: 50 mV/div VOUT: 20 mV/div IOUT: 500 mA/div IOUT: 1 A/div Figure 58. Load Transient Response (IOUT = 0 A ↔ 1 A) www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 -180 1000 Figure 59. Output Ripple Voltage (IOUT = 2 A) 30/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C PCB Layout Design PCB layout design for DC/DC converter is very important. Appropriate layout can avoid various problems concerning power supply circuit. Figure 60 to 62 show the current path in a buck DC/DC converter circuit. The Loop 1 in Figure 60 is a current path when High Side Switch is ON and Low Side Switch is OFF, the Loop 2 in Figure 61 is when High Side Switch is OFF and Low Side Switch is ON. The thick line in Figure 62 shows the difference between Loop1 and Loop2. The current in thick line change sharply each time the switching element High Side and Low Side Switch change from OFF to ON, and vice versa. These sharp changes induce a waveform with harmonics in this loop. Therefore, the loop area of thick line that is consisted by input capacitor and IC should be as small as possible to minimize noise. For more details, refer to application note of switching regulator series “PCB Layout Techniques of Buck Converter”. Loop1 VIN High Side Switch VOUT L CIN COUT Low Side Switch GND GND Figure 60. Current Path when High Side Switch = ON, Low Side Switch = OFF VIN High Side Switch VOUT L CIN COUT Loop2 Low Side Switch GND GND Figure 61. Current Path when High Side Switch = OFF, Low Side Switch = ON VIN VOUT L CIN COUT High Side FET Low Side FET GND GND Figure 62. Difference of Current and Critical Area in Layout www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 31/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C PCB Layout Design – continued When designing the PCB layout, Pay extra attention to the following points. • Connect the input capacitor CIN as close as possible to the VIN pin and GND pin on the same plane as the IC. • Switching nodes such as SW are susceptible to noise due to AC coupling with other nodes. Route the inductor pattern as thick and as short as possible. • R1 and R2 shall be located as close as possible to the FB pin and the wiring between R1 and R2 to the FB pin shall be as short as possible. • Provide line connected to FB far from the SW nodes. • R100 is provided for the measurement of feedback frequency characteristics (optional). By inserting a resistor into R100, it is possible to measure the frequency characteristics of feedback (phase margin) using FRA etc. R100 is short-circuited for normal use. R2 R1 Css IC R100 CIN L1 COUT Example of Evaluation Board Layout (Top View) Example of Evaluation Board Layout (Bottom View) Figure 63. Example of Evaluation Board Layout www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 32/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Power Dissipation For thermal design, be sure to operate the IC within the following conditions. (Since the temperatures described hereunder are all guaranteed temperatures, take margin into account.) 1. 2. The ambient temperature Ta is to be 125 °C or less. The chip junction temperature Tj is to be 150 °C or less. The chip junction temperature Tj can be considered in the following two patterns: 1. To obtain Tj from the package surface center temperature Tt in actual use 𝑇𝑗 = 𝑇𝑡 + 𝜓𝐽𝑇 × 𝑊 [°C] 2. To obtain Tj from the ambient temperature Ta 𝑇𝑗 = 𝑇𝑎 + 𝜃𝐽𝐴 × 𝑊 [°C] Where: 𝜓𝐽𝑇 is junction to top characterization parameter (Thermal Resistance) 𝜃𝐽𝐴 is junction to ambient (Thermal Resistance) The heat loss W of the IC can be obtained by the formula shown below: 𝑉𝑂𝑈𝑇 𝑉𝑂𝑈𝑇 ) + 𝑅𝑂𝑁𝐿 × 𝐼𝑂𝑈𝑇 2 (1 − 𝑉𝐼𝑁 𝑉𝐼𝑁 1 +𝑉𝐼𝑁 × 𝐼𝐶𝐶 + 2 × (𝑡𝑟 + 𝑡𝑓) × 𝑉𝐼𝑁 × 𝐼𝑂𝑈𝑇 × 𝑓𝑆𝑊 [W] 𝑊 = 𝑅𝑂𝑁𝐻 × 𝐼𝑂𝑈𝑇 2 × Where: 𝑅𝑂𝑁𝐻 𝑅𝑂𝑁𝐿 𝐼𝑂𝑈𝑇 𝑉𝑂𝑈𝑇 𝑉𝐼𝑁 𝐼𝐶𝐶 𝑡𝑟 𝑡𝑓 𝑓𝑆𝑊 is the High Side FET ON Resistance (Electrical Characteristics) [Ω] is the Low Side FET ON Resistance (Electrical Characteristics) [Ω] is the Output Current [A] is the Output Voltage [V] is the Input Voltage [V] is the Circuit Current (Electrical Characteristics) [A] is the Switching Rise Time [s] (Typ:3 ns) is the Switching Fall Time [s] (Typ:3 ns) is the Switching Frequency (Electrical Characteristics) [Hz] tf (3 ns) tr (3 ns) VIN 1 1. 𝑅𝑂𝑁𝐻 × 𝐼𝑂𝑈𝑇 2 2. 𝑅𝑂𝑁𝐿 × 𝐼𝑂𝑈𝑇 2 VSW 3. GND 1 2 × (𝑡𝑟 + 𝑡𝑓) × 𝑉𝐼𝑁 × 𝐼𝑂𝑈𝑇 × 𝑓𝑆𝑊 3 2 1 fsw Figure 64. SW Waveform www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 33/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C I/O Equivalence Circuits (Note 1) 1. 2. SW 3. SS VIN VIN 40 kΩ SW SS GND 100 kΩ GND GND GND 4. FB 5. PGD 20 kΩ FB PGD 10 kΩ 50 Ω GND 10 kΩ GND GND 10 kΩ 6. EN 100 kΩ EN 150 kΩ GND 10 kΩ 850 kΩ GND GND GND (Note 1) Resistance value is Typical. www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 34/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C 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 pins. 2. Power Supply Lines Design the PCB layout pattern to provide low impedance supply lines. 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. However, pins that drive inductive loads (e.g. motor driver outputs, DC-DC converter outputs) may inevitably go below ground due to back EMF or electromotive force. In such cases, the user should make sure that such voltages going below ground will not cause the IC and the system to malfunction by examining carefully all relevant factors and conditions such as motor characteristics, supply voltage, operating frequency and PCB wiring to name a few. 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. Recommended Operating Conditions The function and operation of the IC are guaranteed within the range specified by the recommended operating conditions. The characteristic values are guaranteed only under the conditions of each item specified by the electrical characteristics. 6. 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. 7. 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. 8. 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. 9. Unused Input Pins Input pins 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 pins should be connected to the power supply or ground line. www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 35/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Operational Notes – continued 10. Regarding the Input Pin 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 65. Example of Monolithic IC Structure 11. Ceramic Capacitor When using a ceramic capacitor, determine a capacitance value considering the change of capacitance with temperature and the decrease in nominal capacitance due to DC bias and others. 12. 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 maximum junction temperature 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 power 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. 13. Over Current Protection Circuit (OCP) This IC incorporates an integrated overcurrent protection circuit that is activated when the load is shorted. This protection circuit is effective in preventing damage due to sudden and unexpected incidents. However, the IC should not be used in applications characterized by continuous operation or transitioning of the protection circuit. www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 36/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Ordering Information B D 9 S 2 3 1 N U X Package VSON008X2020 - CE2 Product class C: for Automotive applications Packaging and forming specification E2: Embossed tape and reel Marking Diagram VSON008X2020 (TOP VIEW) Part Number Marking D9S LOT Number 2 3 1 Pin 1 Mark www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 37/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Physical Dimension and Packing Information Package Name www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 VSON008X2020 38/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 BD9S231NUX-C Revision History Date Revision 04.Jun.2021 001 Changes New Release www.rohm.com © 2021 ROHM Co., Ltd. All rights reserved. TSZ22111 • 15 • 001 39/39 TSZ02201-0T4T0AA01600-1-2 04.Jun.2021 Rev.001 Notice Precaution on using ROHM Products 1. If you intend to use our Products in devices requiring extremely high reliability (such as medical equipment (Note 1), aircraft/spacecraft, nuclear power controllers, 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 CLASSⅢ CLASSⅡb CLASSⅢ CLASSⅢ CLASSⅣ CLASSⅢ 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 not designed 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 (Exclude cases where no-clean type fluxes is used. However, recommend sufficiently about the residue.); 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-PAA-E © 2015 ROHM Co., Ltd. All rights reserved. Rev.004 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 Cl 2, 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 A two-dimensional barcode 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. 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Rev.004 Datasheet General Precaution 1. Before you use our Products, you are requested to carefully read this document and fully understand its contents. ROHM shall not be in any way responsible or liable for failure, malfunction or accident arising from the use of any ROHM’s Products against warning, caution or note contained in this document. 2. All information contained in this document is current as of the issuing date and subject to change without any prior notice. Before purchasing or using ROHM’s Products, please confirm the latest information with a ROHM sales representative. 3. The information contained in this document is provided on an “as is” basis and ROHM does not warrant that all information contained in this document is accurate and/or error-free. ROHM shall not be in any way responsible or liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccuracy or errors of or concerning such information. Notice – WE © 2015 ROHM Co., Ltd. All rights reserved. Rev.001