HIGH-VOLTAGE INVERTING
DC-DC CONVERTER
SC1650
TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com
January 29, 1998
DESCRIPTION
FEATURES
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
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4V to 24V input voltage operation
Adjustable output voltage up to -40V
Low quiescent current at 100µA
Pulse frequency modulation maintains high
efficiency (max 90%)
100kHz to 320kHz switching frequency
Power-Saving shutdown mode (8µA typical)
High efficiency with low cost external PNP bipolar
transistor
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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.
APPLICATIONS
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Negative LCD contrast bias for
1. Notebook & palmtop computers
2. Pen-based data systems
3. Portable data collection terminals
4. Personal digital assistants
Negative voltage supplies
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BLOCK DIAGRAM
ORDERING INFORMATION
DEVICE(1)
VOUT
PACKAGE
SC1650CS
Adj
SO-8
Note:
(1) Add suffix ‘TR’ for tape and reel.
ABSOLUTE MAXIMUM RATINGS
Parameter
Symbol Maximum Units
V+
Supply Voltage
SHDN Voltage
24
15
V
V
VSHDN
PIN CONFIGURATION
Operating
Temperature
Range
TA
0 to 70
°C
Storage
Temperature
Range
TSTG
-65 to 125
°C
© 1997 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320