Rev. 1.00

2

April 19, 2012

HT7939A

Block Diagram

S

R

R

Q

1. 2M Hz

OS C

UV LO = 2. 1V

OT P

VI N

GN D

FB

Ra mp

OV P

OV P

Pr ot ec t

BG

SW

EN

17. 6V ( 39A -1 )

32. 0V ( 39A -2 )

Pin Assignment

SW

GN D

To p Vi ew

VI NE N

FB

12

3

4

6

5

OV P

SO T 23- 6

Pin Descriptin

PIN No.

PIN Name

Description

1

SW

Switching pin. Connected to inductor and diode.

2

GND

Ground.

3

FB

Feedback pin. Reference voltage. The HT7939A feedback voltage is 0.2V.

4

EN

Shutdown & Dimming control input. Do not allow this pin to float.

5

OVP

Over voltage protection pin which is connected to the output.

6

VIN

The input supply pin for the IC. Connect VIN to a supply voltage between 2.6V~5.5V.