BD9DA00MF datasheet(20/53 Pages) ROHM

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BD9DA00MF

Datasheet

TSZ02201-0J2J0AB01940-1-2

18.Mar.2025 Rev.001

www.rohm.com

TSZ22111 • 15 • 001

Function Explanations

1. Basic Operation

(1) DC/DC Converter Operation

BD9DA00MF is a synchronous buck DC/DC converter that has original on-time control. The device operates with

MODE pin setting. For the operation mode setting method, refer to Function Explanations 1. Basic Operation (11)

Control Mode Selectable Function. When the operating mode is Light Load Mode (LLM), it utilizes switching operation

in Continuous Conduction Mode (CCM) control for heavier load, and it operates in LLM control at lighter load to improve

efficiency. When the operating mode is Forced CCM, the device operates in CCM control regardless of the output load.

Figure 38. Efficiency Image between Light Load Mode Control and CCM Mode Control

(2) Enable Control

The start-up and shutdown can be controlled by the EN voltage (VEN). When VEN becomes 1.22 V (Typ) or more, the

internal circuit is activated and the device starts up. When VEN becomes 1.02 V (Typ) or less, the device shuts down.

In the shutdown mode, the High-Side FET and the Low-Side FET are turned off and the SW pin is connected to GND

through an internal discharge resistor RON_DIS = 70 Ω (Typ) and it discharges the output voltage VOUT to 10 % (Typ) of

the setting voltage.

0 V

Start-up

VENH

VENL

VEN

VOUT

0 V

VIN

Shutdown

Discharged to 10 %

Figure 39. Start-up and Shutdown with Enable Control Timing Chart

CCM Control

Output Current IOUT [A]

Light Load Mode Control

Forced CCM Mode Control

BD9DA00MF Datasheet(PDF) 20 Page - Rohm