LD7577

2

Leadtrend Technology Corporation

www.leadtrend.com.tw

LD7577-DS-01 January 2009

Pin Configuration

YY:

Year code

WW:

Week code

PP:

Production code

SOP-8 & DIP-8 (TOP VIEW)

1

8

2

3

4

7

6

5

TOP MARK

YYWWPP

Ordering Information

Part number

Package

Top Mark

Shipping

LD7577 GS

SOP-8

Green package

LD7577GS

2500 /tape & reel

LD7577 GN

DIP-8

Green package

LD7577GN

3600 /tube /Carton

The LD7577 is ROHS compliant.

Pin Descriptions

PIN

NAME

FUNCTION

1

BNO

Brownout Protection Pin. Connect a resistor divider between this pin and bulk

capacitor voltage to set the brownout level. If the voltage is less than threshold

voltage, the PWM output will be disabled. As soon as the voltage is over 4.0V, the

OVP will be tripped and the gate drive will be turned off.

2

COMP

Voltage feedback pin. By connecting a photo-coupler to close the control loop, it can

achieve the regulation.

3

CS

Current sense pin. Connect it to sense the MOSFET current.

4

GND

Ground.

5

OUT

Gate drive output to drive the external MOSFET.

6

VCC

Supply voltage pin.

7

NC

Unconnected Pin.

8

HV

Connect this pin to positive terminal of bulk capacitor to provide the startup current

for the controller. When VCC voltage trips UVLO(on), this HV loop will be turned off

to save the power loss of the startup circuit.