RT8457A

2

DS8457A-02

September 2013

www.richtek.com

©

Copyright

2013 Richtek Technology Corporation. All rights reserved.

is a registered trademark of Richtek Technology Corporation.

Functional Pin Description

Pin No.

Pin Name

Pin Function

1

VCC

Supply Voltage Input. A 0.1

μF bypass capacitor should be connected between VCC

and GND.

2

REF

Internal Reference Voltage. A 0.1

μF bypass capacitor is required between this pin and

GND.

3

OUT

Open-Collector Output. Connect this pin to an opto-coupler with a current limiting

resistor.

4

GND

Ground.

5

OVP

Over-Voltage Protection Sense Input with 1V Threshold.

6

LED

LED Current Sense Input. The sense threshold is 170mV when ACTL pin voltage is

higher than 1.1V. The threshold can be adjusted by the ACTL pin.

7

ACTL

Analog Dimming Control Input. The LED current sense threshold is at the maximum

when the ACTL pin voltage is higher than 1.1V. Must place a 100k

Ω from the ACTL pin

to GND to avoid the noise interference.

8

NC

No Internal Connection.

Ordering Information

Note :

Richtek products are :

RoHS compliant and compatible with the current require-

ments of IPC/JEDEC J-STD-020.

Suitable for use in SnPb or Pb-free soldering processes.

Pin Configurations

(TOP VIEW)

SOP-8

REF

OUT

VCC

GND

NC

ACTL

OVP

LED

2

3

4

5

6

7

8

RT8457A

Package Type

S : SOP-8

Lead Plating System

G : Green (Halogen Free and Pb Free)