RT9709

2

DS9709-02 April 2011

www.richtek.com

Function Block Diagram

Pin No.

WDFN-12L 4x3

WDFN-10L 3x3

Pin Name

Pin Function

1, 2

1, 2

VIN

Input Power Source Pin.

3

3

GND

Ground Pin.

4

4

WRN

This is an open-drain logic output that turns LOW when any

protection event occurs.

5, 6, 12

5

NC

No Internal Connection.

7

6

EN

Enable Input Pin. Pull this pin to low or leave it floating to

enable the IC. Force this pin to high to disable the IC.

8

7

VB

Battery Voltage Monitoring Input Pin. This pin is connected to

the battery pack positive terminal via resistor.

9

8

ILIM

Over-Current Protection Threshold Setting Pin. Connect a

resistor between this pin and GND to set the OCP threshold.

10, 11

9, 10

VOUT

Output Voltage Pin. Output through the MOSFET.

13 (Expose Pad) 11 (Exposed Pad) GND

The exposed pad must be soldered to a large PCB and

connected to GND for maximum thermal dissipation.

Functional Pin Description

Typical Application Circuit

Control

Logic

Driver

OCP

OCP

Seting

BATOVP

Buffer

OTP

UVLO

INOVP

BASE

EN

Logic

WRN

GND

VOUT

ILIM

VB

VIN

EN

RT9709/A/B

VIN

VIN

NC

WRN

GND

VOUT

VOUT

ILIM

VB

EN

VIN

Charger

+

Battery

WRN

EN