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BD9DA00MF

Datasheet

TSZ02201-0J2J0AB01940-1-2

18.Mar.2025 Rev.001

www.rohm.com

TSZ22111 • 15 • 001

1. Basic Operation – continued

(11) Control Mode Selectable Function

BD9DA00MF has the MODE pin to set the switching frequency and operation mode. It cannot be changed during

operation.

Table 2. Control Mode Setting

MODE Pin Condition

Switching Frequency

Operation Mode

Short to VCC

600 kHz (Typ)

Light Load Mode (LLM)

240 kΩ to GND

800 kHz (Typ)

Light Load Mode (LLM)

120 kΩ to GND

1 MHz (Typ)

Light Load Mode (LLM)

Short to GND

600 kHz (Typ)

Forced CCM Mode

30 kΩ to GND

800 kHz (Typ)

Forced CCM Mode

62 kΩ to GND

1 MHz (Typ)

Forced CCM Mode

(12) External Bias On VCC Pin Function

VCC outputs 3.0 V (Typ) from the internal LDO, it can also be applied externally. External bias improves efficiency and

allows operation at 2.7 V ≤ VIN ≤ 4.0 V.

When applying an external bias on the VCC pin, please note the following.

·The externally applied voltage VCC_EXT should be 3.13 V ≤ VCC_EXT ≤ 3.60 V.

·It should be enabled in a sequence where external application on the VCC pin completes before either the start-up by

EN signal or VIN UVLO release.

(13) Remote Sense Function

BD9DA00MF has a remote sense function using the FB and RGND pins. The remote sense function compensates for

output voltage drop due to the PCB wiring resistance. When this function is available, the VOUT connection of the remote

sensing signal VOUTSNS+ must be connected to the feedback resistor RUP. The ground connection of the remote sensing

signal VOUTSNS- must be connected to the RGND pin. To maintain stable output voltage and minimize the ripple voltage,

the pair of remote sensing lines must stay away from any noise sources such as inductor, SW nodes, and high

frequency clock lines. In addition, connect a capacitor CRGND of 0.1 μF or more between VOUTSNS+ and VOUTSNS-. In this

case, It is recommended that RUP, RDOWN, CFB, and CRGND are placed at nearby BD9DA00MF. If the remote sense

function is not used, RGND should be shorted to AGND with shortest trace. In this case CSS1 can be deleted, but CSS2

can be set within the range described in Selection of Components Externally Connected 4. Soft Start Capacitor.

It is recommended to use the RGND pin with an operating range of -50 mV to +50 mV.

Figure 41. Circuit with Remote Sense Function

Figure 42. Circuit when Remote Sense Function is not used

VOUT

RUP

RDOWN

RGND

SS/REF

CFB

CSS2

AGND

VOUTSNS+

RUP

RDOWN

RGND

SS/REF

CFB

CSS1

CSS2

AGND

CRGND

VOUTSNS-

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