RT6318B/C

3

DS6318B/C-01 December 2021

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Functional Pin Description

pin No.

Pin Name

Pin Function

1

BOOT

Boot-strap pin. Supply high-side gate driver. A 0.1

F ceramic capacitor and

at least 10

 RBOOT are connected between this pin and LX pin.

2,3

LX

Inductor pin. Connect this pin to the switching node of inductor.

4

PGND

Power ground.

5

VIN

Input pin. Decouple this pin to GND pin with at least 10

F ceramic cap.

6

EN

(RT6318B)

Enable control. Pull this pin high to turn on the Buck. Do not leave this pin

floating. EN pin will also be used to set USM mode, when EN pin voltage is

between 0.8V and 1.7V, it will enter USM mode, if EN pin voltage is between

2.3V and 23V, then it is normal mode.

EN

(RT6318C)

Enable control. Pull this pin high to turn on the Buck. Do not leave this pin

floating. EN pin will also be used to set USM mode, when EN pin voltage is

between 0.8V and 1.7V, it will enter USM mode, if EN pin voltage is between

2.3V and 23V, then it is normal mode.

7

PGOOD

Power good indicator. Open drain output when the output voltage is higher

than 90% of regulation point.

8

AGND

Analog ground.

9

VCC

(RT6318B)

5V linear regulator output for internal control circuit. A capacitor (typical 1

F)

should be connected to AGND. Don’t connect to external Load.

FF

(RT6318C)

Output feedforward pin. Connect RC network from the output to this pin.

10

VOUT

(RT6318B)

Output pin. Connect to the output of DC-DC regulator. The pin also provides

the bypass input for 3.3V LDO.

VOUT

(RT6318C)

Output pin. Connect to the output of DC-DC regulator. The pin also provide

the bypass input for 5V LDO.

11

LDO3

(RT6318B)

Internal 3.3V LDO output. Bypass a capacitor to GND. This pin is also

capable sourcing 100mA current for external load.

VCC

(RT6318C)

5V linear regulator output for internal control circuit. A capacitor (typical 1

F)

should be connected to AGND. Don’t connect to external load.

12

FF

(RT6318B)

Output feedforward pin. Connect RC network from the output to this pin.

LDO5

(RT6318C)

Internal 5V LDO output. Bypass a capacitor to GND. This pin is also capable

sourcing 100mA current for external load.