CAT661
High Frequency 100mA CMOS Charge Pump, Inverter/Doubler
FEATURES
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Converts V+ to V- or V+ to 2V+
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Low output resistance, 10Ω max.
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High power efficiency
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Selectable charge pump frequency of 25kHz
H
GEN
FR
ALO
EE
LE
A
D
F
R
E
E
TM
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Pin-compatible to MAX660, LTC660 with higher
frequency operation
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Available in 8-pin SOIC andDIP packages
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Lead-free, halogen-free package option
or 135kHz; optimize capacitor size.
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Low quiescent current
APPLICATIONS
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Negative voltage generator
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Voltage doubler
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Voltage splitter
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Low EMI power source
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GaAs FET biasing
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Lithium battery power supply
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Instrumentation
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LCD contrast bias
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Cellular phones, pagers
DESCRIPTION
The CAT661 is a charge-pump voltage converter. It can
invert a positive input voltage to a negative output. Only
two external capacitors are needed. With a guaranteed
100mA output current capability, the CAT661 can replace
a switching regulator and its inductor. Lower EMI is
achieved due to the absence of an inductor.
In addition, the CAT661 can double a voltage supplied
from a battery or power supply. Inputs from 2.5V to 5.5V
will yield a doubled, 5V to 11V output.
A Frequency Control pin (BOOST/FC) is provided to
select either a high (typically 135kHz) or low (25kHz)
internal oscillator frequency, thus allowing quiescent
current vs. capacitor size trade-offs to be made. The
135kHz frequency is selected when the FC pin is
connected to V+. The operating frequency can also be
adjusted with an external capacitor at the OSC pin or by
driving OSC with an external clock.
Both 8-pin DIP and SO packages are available. For die
availability, contact Catalyst Semiconductor marketing.
The CAT661 can replace the MAX660 and the LTC660
in applications where higher oscillator frequency and
smaller capacitors are needed. In addition, the CAT661
is pin compatible with the 7660/1044, offering an easy
upgrade for applications with 100mA loads.
TYPICAL APPLICATION
+VIN
1.5V to 5.5V
1
C1
+
BOOST/FC
CAP+
GND
CAP-
V+
OSC
8
7
6
5
Inverted
Negative
Voltage
Output
C1
+
1
2
3
4
BOOST/FC
CAP+
GND
CAP-
V+
OSC
LV
OUT
8
7
6
5
Doubled
Positive
Voltage
Output
2
3
4
CAT661
CAT661
LV
OUT
VIN = 2.5V to 5.5V
VOLTAGE INVERTER
POSITIVE VOLTAGE DOUBLER
© Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
1
Doc. No. MD-5003, Rev. K
CATALYST [ CATALYST SEMICONDUCTOR ]
