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© 2020 ROHM Co., Ltd.
No. 63UG064E Rev. 002
Apr. 2022
User’s Guide
Switching Regulator Series
1ch buck switching regulator
BD9B305QUZ EVK User’s Guide
BD9B305QUZ-EVK-001 (5V input
→
1.8V, 3A output)
Introduction
This user’s guide will provide the necessary steps to operate BD9B305QUZ-EVK-001 and evaluate BD9B305QUZ, a 1-channel
Buck DC/DC converter. Component selection, operating procedures, and evaluation data are also included in this guide.
Description
This EVK was developed for the customers to evaluate ROHM’s synchronous buck DC/DC converter, BD9B305QUZ.
The operating topology is on-time control and operating frequency is fixed to 1MHz which features fast transient response.
The IC supports Light Load Mode and an internal 50mΩ N-channel MOSFET for high-side and 40mΩ N-channel MOSFET for
low-side are integrated so that the total efficiency and thermal property get improved. The built-in Soft Start circuit prevents inrush
current during startup and its value can be adjusted by changing the capacitance value for SS pin. There are a number of
protection circuits present in this IC such as UVLO (Under Voltage Lock Out), TSD (Thermal Shutdown Detection), OCP (Over
Current Protection), SCP (Short Circuit Protection), and OVP (Over Voltage Protection) and output discharge function which
provide higher system reliablity. Power Good function makes an easy sequence control in the system. The board is set in typical
condition and the component values are tuned for 1.8V output voltage setting.
Application
●
Step-down Power Supply for SoC, FPGA
●
Laptop PC / Tablet PC / Server
●
LDC TV
●
Storage Device (HDD / SSD)
●
Printer, OA Equipment
●
Distribution power supply / Secondary power supply
EVK Operating conditions
Parameter
Min
Typ
Max
Units
Conditions
Input Voltage
2.7
5.5
V
Output Voltage
1.8
V
VOUT=1.8V setting
Output Current
3.0
A
Operating Frequency
1
MHz
Maximum Efficiency
92
%
VIN=5V, IOUT=1A
UVLO Detect Voltage
2.450
V
VIN sweep down
UVLO Release Voltage
2.550
V
VIN sweep up
Soft Start Time
1
ms
SS pin is open
