SS6660
Switched-Capacitor Voltage Converter
FEATURES
Low output impedance (typ. 35Ω at
V
IN
=5V)
Improved direct replacement for 7660
Operation from 1.5V to 6V
DESCRIPTION
The SS6660 is a monolithic CMOS switched-
capacitor voltage converter. Designed to be an
improved direct replacement for the popular 7660
and LTC1044, the main function of the SS6660
is to convert a positive input voltage in the range
of 1.5V to 6V to the corresponding negative
output voltage in the range of 11.5V to -6V.
The input voltage can also be doubled (V
OUT
= 2V
IN
), divided (V
OUT
= V
IN
/2), or multiplied
(V
OUT
= ±nV
IN
) as shown in the application
examples.
The chip contains a series DC power supply
regulator, oscillator, control circuitry and four
output power MOSFET switches. The frequency
of the oscillator can be lowered by the addition of
an external capacitor to the OSC pin, or the
oscillator may be over-driven by an external clock.
No external diode required
Simple conversion from +5V to -5V
Low quiescent current (typ. 36µA at V
IN
=5V)
High power efficiency (typ. 98%)
Boost pin for higher switching frequency
Improved SCR latchup protection
APPLICATIONS
RS-232 Power Supplies
Handheld Instruments
Data Acquisition Systems
Supply Splitter V
OUT
= ±V
IN
/2
Operational Amplifier Supplies
Panel Meter
TYPICAL APPLICATION CIRCUIT
This boost function is available to raise the
oscillator frequency to optimize performance in
specific applications. The "LV" terminal may be
tied to GND to improve low input-voltage (V
IN
≤
3V) operation, or be left floating for input voltages
VIN (1.5V to 6V)
µ
Required for
V
IN
≤
3V
µ
larger than 3V to improve power dissipation.
The SS6660 provides performance superior to
previous designs by combining low output
impedance, low quiescent current with high
efficiency and by eliminating losses from diode
voltage drops. The only external components
required are two low-cost electrolytic capacitors.
SS6660
Negative voltage converter
Rev.2.02 1/29/2004
www.SiliconStandard.com
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Embedded System
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