RT8489

3

DS8489-00 November 2012

www.richtek.com

©

Copyright 2012 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Pin No.

Pin Name

Pin Function

13, 16, 19, 22 SENSEx

Source of External MOSFETx (x = 1 to 4).

The SENSEx pins are regulated around 225mV. Connect a sense resistor from

14, 17, 20, 23 GATEx

Gate Drive Output for External MOSFETx (x = 1 to 4).

15, 18, 21, 24 LEDx

LED String Voltage Sense Input. Connect these pins to the Drain of External

MOSFETx (x = 1 to 4). Short the pin to GND if not used.

Function Block Diagram

+

-

PWM

Control

OSC

VOUT

Regulation

Unit

+

-

+

-

10V

VCC

5.5V

1.23V

RSET

OVP

VC

LED1

LED2

LED3

LED4

SS

GBIAS

GATE

ISENSE

LED1

GATE1

SENSE1

LED2

GATE2

SENSE2

LED3

GATE3

SENSE3

LED4

GATE4

SENSE4

GBIAS

3.2V

+

-

+

-

GBIAS

+

-

GBIAS

8µA

3.2V

+

-

Shutdown

1.4V

EN

+

-

3.2V

1.4V

1.4V

DCTL

ACTL

+

-

GND

GBIAS

3.2V

3.2V

3.2V

+

-