Datasheet 2.7 V to 5.5 V Input, 3.0 A Integrated MOSFET Single Synchronous Bu ck DC/DC Converter BD9B305QUZ General Description Key Specifications BD9B305QUZ is a synchronous buck DC/DC converter Input Voltage Range: 2.7 V to 5.5 V with built-in low on-resistance power MOSFETs. It is Output Voltage Range: 0.6 V to VIN x 0.8 V capable of providing current up to 3 A. It features fast Output Current: 3.0 A (Max) transient response due to constant on-time control Switching Frequency: 1 MHz (Typ) system. The Light Load Mode control improves efficiency High-Side FET ON Resistance: 50 m (Typ) in light-load conditions. It is ideal for reducing standby Low-Side FET ON Resistance: 40 m (Typ) power consumption of equipment. Power Good function Shutdown Current: 0 A (Typ) makes it possible for system to control sequence. It achieves the high power density and offer a small Package W (Typ) x D (Typ) x H (Max) footprint on the PCB by employing small package. VMMP08LZ2020 2.00 mm x 2.00 mm x 0.40 mm Features Single Synchronous Buck DC/DC Converter Constant On-time Control Light Load Mode Control Adjustable Soft Start Power Good Output Output Capacitor Discharge Function Over Voltage Protection (OVP) Over Current Protection (OCP) Short Circuit Protection (SCP) Thermal Shutdown Protection (TSD) Under Voltage Lockout Protection (UVLO) VMMP08LZ2020 Package Backside Heat Dissipation VMMP08LZ2020 0.5 mm Pitch Applications Step-down Power Supply for SoC, FPGA, Microprocessor Laptop PC / Tablet PC / Server LCD TV Storage Device (HDD / SSD) Printer, OA Equipment Distributed Power Supply, Secondary Power Supply Typical Application Circuit BD9B305QUZ V IN VIN PGD BOOT C IN 0.1 F V OUT GND SW L 1 V R C EN 1 FB EN C OUT SS FB R 2 Product structure : Silicon integrated circuit This product has no designed protection against radioactive rays. www.rohm.com TSZ02201-0F3F0AJ00250-1-2 2019 ROHM Co., Ltd. All rights reserved. 1/41 TSZ22111 14 001 08.Mar.2019 Rev.001 BD9B305QUZ Pin Configuration (TOP VIEW) EXP-PAD BOOT 1 8 GND SW 2 7 VIN PGD 3 6 EN FB 4 5 SS Pin Descriptions Pin No. Pin Name Function Pin for bootstrap. Connect a bootstrap capacitor of 0.1 F between this pin and the SW pin. 1 BOOT The voltage of this pin is the gate drive voltage of the High-Side FET. Switch pin. This pin is connected to the source of the High-Side FET and the drain of the 2 SW Low-Side FET. Connect a bootstrap capacitor of 0.1 F between this pin and the BOOT pin. In addition, connect an inductor considering the direct current superimposition characteristic. Power Good pin. This pin is an open drain output that requires a pull-up resistor. See page 3 PGD 17 for setting the resistance. If not used, this pin can be left floating or connected to the ground. Output voltage feedback pin. See page 31 for how to calculate the resistances of the output 4 FB voltage setting. Pin for setting the soft start time of output voltage. The soft start time is 1 ms (Typ) when the 5 SS SS pin is left floating. A ceramic capacitor connected to the SS pin makes the soft start time more than 1 ms. See page 31 for how to calculate the capacitance. Enable pin. The device starts up with setting VEN to 0.920 V (Typ) or more. The device enters 6 EN the shutdown mode with setting VEN to 0.875 V (Typ) or less. This pin must be terminated. Power supply pin. Connecting 0.1 F (Typ) and 22 F (Typ) ceramic capacitors is 7 VIN recommended. The detail of a selection is described in page 31. 8 GND Ground pin. A backside heat dissipation exposed pad. Connecting to the PCB power ground plane by - EXP-PAD using thermal vias provides excellent heat dissipation characteristics. See page 34 to 35 for the detailed PCB layout design. www.rohm.com TSZ02201-0F3F0AJ00250-1-2 2019 ROHM Co., Ltd. All rights reserved. 2/41 TSZ22111 15 001 08.Mar.2019 Rev.001