© 1997 SEMTECH CORP.

652 MITCHELL ROAD NEWBURY PARK CA 91320

HIGH-VOLTAGE INVERTING

DC-DC CONVERTER

SC1650

January 29, 1998

ORDERING INFORMATION

Note:

(1) Add suffix ‘TR’ for tape and reel.

FEATURES

efficiency (max 90%)

transistor

DESCRIPTION

The SC1650 is a high performance inverting DC-DC

converter, designed to drive an external power switch

to generate programmable negative voltages. In the

particularly suitable LCD bias contrast application,

maximum efficiency of 90% can be achieved with low

cost PNP bipolar transistor drivers. The 4V to 24V

input operation range allows the SC1650 to be

powered directly by the battery pack in most battery-

operated applications for greater efficiency. The output

voltage can be scaled to -40V by two external

resistors. A pulse frequency modulation scheme is

employed to maintain high efficiency conversion under

wide input voltage ranges. Quiescent current is about

100µA and can be reduced to 8µA in shutdown mode.

With a switching frequency range of 100kHz to

320kHz, small size switching components may be

used, which is ideal for battery powered portable

equipment such as notebook and palmtop computers.

TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com

APPLICATIONS

1.

Notebook & palmtop computers

2.

Pen-based data systems

3.

Portable data collection terminals

4.

Personal digital assistants

ABSOLUTE MAXIMUM RATINGS

Parameter

Symbol

Maximum

Units

Supply Voltage

V

+

24

V

SHDN Voltage

V

SHDN

15

V

Operating

Temperature

Range

T

A

0 to 70

°C

Storage

Temperature

Range

T

STG

-65 to 125

°C

PIN CONFIGURATION

BLOCK DIAGRAM

DEVICE

(1)

V

OUT

PACKAGE

SC1650CS

Adj

SO-8