CAT661
High Frequency 100mA CMOS Charge Pump, Inverter/Doubler
FEATURES
s
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
LOGEN
FR
A
EE
LE
A
D
F
R
E
E
TM
s
Pin-compatible to MAX660, LTC660 with higher
frequency operation
s
Available in 8-pin SOIC andDIP packages
s
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
s
Voltage splitter
s
Low EMI power source
s
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
CAT661
PIN CONFIGURATION
SOIC 8-Lead (V)
PDIP 8-Lead (L)
BOOST/FC 1
CAP+ 2
GND 3
CAP- 4
CAT661
8 V+
7 OSC
6 LV
5 OUT
(Top View)
PIN DESCRIPTIONS
Circuit Configuration
Pin Number
Name
1
Boost/FC
Inverter
Freqency Control for the internal oscillator.
With an external oscillator BOOST/FC has
no effect.
Boost/FC Oscillator Frequency
Open
V+
2
3
4
5
6
CAP+
GND
CAP-
OUT
LV
25kHz typical, 10kHz minimum
Doubler
Same as inverter.
Oscillator Frequency
40kHz typical
135kHz typical, 80kHz minimum 135kHz typical, 40kHz minimum
Same as inverter.
Power supply. Positive voltage input.
Same as inverter.
Power supply ground.
LV must be tied to OUT for all input
voltages.
Charge Pump Capacitor. Positive terminal.
Power Supply Ground.
Charge pump capacitor. Negative terminal.
Output for negative voltage.
Low-Voltage selection pin. When the input
voltage is less than 3V, connect LV to GND.
For input voltages above 3V, LV may be
connected to GND or left open. If OSC is
driven externally, connect LV to GND.
Oscillator control input. An external capacitor
can be connected to lower the oscillator
frequency. An external oscillator can drive
OSC and set the chip operating frequency.
The charge-pump frequency is one-half the
frequency at OSC.
Power supply. Positive voltage input.
7
OSC
Same as inverter. Do not overdrive
OSC in doubling mode. Standard logic
levels will not be suitable. See the
applications section for additional
information.
Positive voltage output.
8
V+
ORDERING INFORMATION
Part Number
CAT661ELA
CAT661EVA
CAT661EVA-T3
Package
PDIP, 8-lead
SOIC
SOIC
Quanity
50/tube
100/tube
3,000/reel
Package
Marking
661ELA
661EVA
661EVA
Note:
All packages are RoHS compliant.
Doc. No. MD-5003, Rev. K
2
CAT661
ABSOLUTE MAXIMUM RATINGS
V+ to GND ............................................................. 6V
Storage Temperature ......................... -65°C to 160°C
Input Voltage (Pins 1, 6 and 7) .. -0.3V to (V+ + 0.3V)
BOOST/FC and OSC Input Voltage ........... The least
negative of (Out - 0.3V) or (V+ - 6V) to (V+ + 0.3V)
Output Short-circuit Duration to GND .............. 1 sec.
(OUT may be shorted to GND for 1 sec without damage but
shorting OUT to V+ should be avoided.)
Lead Soldering Temperature (10 sec) ............. 300°C
ESD Rating-Human Body Model ..................... 2000V
Note: T
A
= Ambient Temperature
These are stress ratings only and functional operation is not
implied. Exposure to absolute maximum ratings for prolongued
time periods may affect device reliability. All voltages are with
respect to ground.
Continuous Power Dissipation (T
A
= 70°C)
Plastic DIP ................................................ 730mW
SO ............................................................ 500mW
TDFN ............................................................... 1W
Operating Ambient Temperature Ranges
CAT661E .............. -40°C to 85°C
ELECTRICAL CHARACTERISTICS
V+ = 5V, C1 = C2 = 100µF, Boost/FC = Open, C
OSC
= 0pF, and Test Circuit is Figure 1 unless otherwise noted.
Temperature is T
A
= T
AMIN
to T
AMAX
unless otherwise noted.
Parameter
Supply Voltage
Supply Current
Output Current
Output Resistance
Symbol
VS
IS
IOUT
RO
Conditions
Inverter: LV = Open. R
L
= 1kΩ
Inverter: LV = GND. R
L
= 1kΩ
Doubler: LV = OUT. R
L
= 1kΩ
BOOST/FC = open, LV = Open
BOOST/FC = V+ , LV = Open
OUT is more negative than -4V
C1 = C2 = 10µF,
BOOST/FC = V+ (C1, C2 ESR
≤
0.5Ω)
C1 = C2 = 100µF (Note 2)
Oscillator Frequency FOSC
(Note 3)
OSC Input Current
Power Efficiency
IOSC
PE
BOOST/FC = Open
BOOST/FC = V+
BOOST/FC = Open
BOOST/FC = V+
R
L
= 1kΩ connected between V+ and
OUT, T
A
= 25
°
C (Doubler)
R
L
= 500Ω connected between GND and
OUT, T
A
= 25
°
C (Inverter)
I
L
= 100mA to GND, T
A
= 25
°
C (Inverter)
Voltage Conversion
Efficiency
1. In Figure 1, test circuit electrolytic capacitors C1 and C2 are 100µF and have 0.2Ω maximum ESR. Higher ESR levels may reduce
efficiency and output voltage.
2. The output resistance is a combination of the internal switch resistance and the external capacitor ESR. For maximum voltage and
efficiency keep external capacitor ESR under 0.2Ω.
3. FOSC is tested with C
OSC
= 100pF to minimize test fixture loading. The test is correlated back to C
OSC
=0pF to simulate the capacitance at
OSC when the device is inserted into a test socket without an external C
OSC
.
Min.
3.0
1.5
2.5
Typ
Max.
5.5
5.5
5.5
Units
V
0.2
1
100
3.5
3.5
10
80
25
135
±2
±10
96
92
98
96
88
99
99.9
0.5
3
mA
mA
10
10
Ω
kHz
µA
%
VEFF
No load, T
A
= 25
°
C
%
3
Doc. No. MD-5003, Rev. K
CAT661
Figure 1. Test Circuit Voltage Inverter
IS
V+
1
2
+
C1
100µF
BOOST/FC
CAP+
GND
CAP-
V+
OSC
LV
OUT
8
7
6
5
V+
5V
External
Oscillator
COSC
RL
IL
VOUT
C2
+ 100µF
3
4
CAT661
TYPICAL OPERATING CHARACTERISTICS
Typical characteristic curves are generated using the circuit in Figure 1. Inverter test conditions are: V+ 5V, LV = GND,
BOOST/FC = Open and T
A
= 25˚C unless otherwise indicated. Note that the charge-pump frequency is one-half the
oscillator frequency.
Supply Current vs. Input Voltage
1400
1200
Supply Current vs. Temperature (No Load)
250
INPUT CURRENT [µA]
INPUT CURRENT [µA]
1000
800
600
400
200
0
1
2
3
4
5
INPUT VOLTAGE [V]
6
FC = open
FC = V+
200
150
100
50
VIN = 5V
VIN = 3V
VIN = 2V
0
-50
-25
0
25
50
75
100
125
TEMPERATURE
[
o
C]
Output Resistance vs. Input Voltage
10
Output Resistance vs. Temperature (50
Ω
load)
8
OUTPUT RESISTANCE [Ω]
OUTPUT RESISTANCE [Ω]
8
6
4
2
0
1
2
3
4
5
INPUT VOLTAGE [V]
6
7
6
5
VIN = 2V
4
3
VIN = 5V
2
-50
-25
0
25 50 75 100 125
TEMPERATURE [
o
C]
VIN = 3V
Doc. No. MD-5003, Rev. K
4
CAT661
TYPICAL OPERATING CHARACTERISTICS
Inverted Output voltage vs. Load, V+ = 5V
5.0
Output Voltage Drop vs. Load Current
1.0
OUTPUT VOLTAGE [V]
INV. OUTPUT VOLTAGE [V]
4.8
4.6
4.4
4.2
4.0
0
20
40
60
80
LOAD CURRENT [mA]
100
0.8
0.6
0.4
0.2
0.0
0
20
40
60
80
100
LOAD CURRENT [mA]
V+ = 3V
V+ = 5V
Oscillator Frequency vs. Supply Voltage
50
Oscillator Frequency vs. Supply Voltage
200
FREQUENCY [kHz]
FREQUENCY [kHz]
40
30
20
10
0
1
2
3
4
5
SUPPLY VOLTAGE [V]
6
FC = Open
160
120
80
40
0
1
2
3
4
5
SUPPLY VOLTAGE [V]
6
FC = V+
Supply Current vs. Oscillator Frequency
10000
100
Efficiency vs. Load Current
INPUT CURRENT [µA]
1000
EFFICIENCY [%]
No
No Load
L d
90
V+ =5V
80
70
60
50
40
0
50
LOAD CURRENT [mA]
100
V+ = 3V
100
10
1
10
100
1000
OSCILLATOR FREQUENCY [KHz]
5
Doc. No. MD-5003, Rev. K
