Datasheet 2.7V to 5.5V Input, 3.0A Integrated MOSFET Single Synchronous Bu ck DC/DC Converter BD9B333GWZ General Description Key Specifications BD9B333GWZ is a synchronous buck DC/DC converter Input Voltage Range: 2.7V to 5.5V with built-in low on-resistance power MOSFETs. This IC, Output Voltage Range: 0.6 V to VIN x 0.8 V which is capable of providing current up to 3A, features Output Current: 3A (Max) fast transient response by employing constant on-time Switching Frequency: 1.3MHz (Typ) control system. It offers high oscillating frequency at low High-Side MOSFET ON Resistance: 23m (Typ) inductance. With its original constant on-time control Low-Side MOSFET ON Resistance: 23m (Typ) method which operates low consumption at light load, Standby Current: 0A (Typ) this product is ideal for equipment and devices that demand minimal standby power consumption. Package W (Typ) x D (Typ) x H (Max) BD9B333GWZ achieves the high power density and offer UCSP35L1 1.98mm x 1.80mm x 0.40mm a small footprint on the PCB by employing small CSP package. Features Single Synchronous Buck DC/DC Converter Constant On-time Control Suitable to Deep-SLLM Over Current Protection Short Circuit Protection Over Voltage Protection Thermal Shutdown Protection Under Voltage Lockout Protection Adjustable Soft Start Power Good Output UCSP35L1 Package (Resin Coating) UCSP35L1 Applications Step-down Power Supply for DSPs, FPGAs, Microprocessors, etc. Laptop PCs/Tablet PCs/Servers LCD TVs Storage Devices (HDDs/SSDs) Printers, OA Equipment Distributed Power Supplies, Secondary Power Supplies Typical Application Circuit V IN V C PGD IN PVIN AVIN PGD BOOT Enable EN C BST V OUT BD9B333GWZ MODE SW L R C 1 FB SS FB C OUT AGND PGND R 2 Figure 1. Application Circuit (MODE=L) Product structure : Silicon monolithic integrated circuit This product has no designed protection against radioactive rays . www.rohm.com TSZ02201-0F3F0AJ00120-1-2 2017 ROHM Co., Ltd. All rights reserved. 1/40 TSZ22111 14 001 16.Jun.2017 Rev.001 BD9B333GWZ Pin Configuration (BOTTOM VIEW) D3 D4 D1 D2 D PVIN PVIN AVIN BOOT C3 C1 C2 C4 C EN SW SW SS B1 B2 B3 B4 B PGD MODE SW SW A1 A2 A3 A4 A FB AGND PGND PGND 1 2 3 4 Figure 2. Pin Configuration Pin Descriptions Pin Pin No. Function Name An inverting input node for the error amplifier and main comparator. A1 FB See page 31 for how to calculate the resistance of the output voltage setting. A2 AGND Ground terminal for the control circuit. A3, A4 PGND Ground terminals for the output stage of the switching regulator. Power Good terminal. A pull-up resistor is needed due to an open drain output. See page 17 B1 PGD for how to specify the resistance. When the FB terminal voltage reaches more than 90% of 0.6V (Typ), the internal Nch MOSFET turns off and the output turns High. Terminal for setting switching control mode. Connecting this terminal to AVIN forces the device to operate in the fixed frequency PWM mode. Connecting this terminal to ground B2 MODE enables the Deep-SLLM control and the mode is automatically switched between the Deep-SLLM control and fixed frequency PWM mode. Please fix this terminal to AVIN or ground. Do not change the control mode during operation. Switch terminals. These terminals are connected to the source of the High-Side MOSFET B3, B4 and drain of the Low-Side MOSFET. Connect a bootstrap capacitor of 0.1F between these SW C3, C4 terminals and BOOT terminal. In addition, connect an inductor considering the direct current superimposition characteristic. Enable terminal. Turning this terminal signal Low (0.5V or less) forces the device to enter the C1 EN shutdown mode. Turning this terminal signal High (1.5V or more) enables the device. This terminal must be properly terminated. Terminal for setting the soft start time. Rising time of output voltage is 1ms (Typ) when SS C2 SS terminal is open. A capacitor connected to the SS terminal makes rising time more than 1ms. See page 32 for how to calculate the capacitance. Terminal for supplying power to the control circuit of the switching regulator. D1 AVIN This terminal is connected to PVIN. Terminal for bootstrap. Connect a bootstrap capacitor of 0.1F between this terminal and SW D2 BOOT terminals. The voltage of this terminal is the gate drive voltage of the High-Side MOSFET. Power supply terminals for the switching regulator. D3, D4 PVIN These terminals supply power to the output stage of the switching regulator. Connecting a 22F ceramic capacitor is recommended. www.rohm.com TSZ02201-0F3F0AJ00120-1-2 2017 ROHM Co., Ltd. All rights reserved. 2/40 TSZ22111 15 001 16.Jun.2017 Rev.001