SC1650 Datasheet, PDF (1/4 Pages) Semtech Corporation – HIGH-VOLTAGE INVERTING DC-DC CONVERTER

HIGH-VOLTAGE INVERTING
DC-DC CONVERTER
SC1650
January 29, 1998
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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.
BLOCK DIAGRAM
FEATURES
• 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
APPLICATIONS
• 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
ORDERING INFORMATION
DEVICE⁽¹⁾
SC1650CS
V_OUT
Adj
Note:
(1) Add suffix ‘TR’ for tape and reel.
PACKAGE
SO-8
PIN CONFIGURATION
ABSOLUTE MAXIMUM RATINGS
Parameter
Supply Voltage
SHDN Voltage
Operating
Temperature
Range
Storage
Temperature
Range
Symbol
V⁺
V_SHDN
T_A
Maximum
24
15
0 to 70
Units
V
V
°C
T_STG
-65 to 125
°C
© 1997 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320