The ADM660 is a pin compatible upgrade for the MAX660,
MAX665, ICL7660 and LTC1046.
The ADM660/ADM8660 is available in 8-pin DIP and narrow-
body SOIC. The ADM660 is also available in a 16-lead TSSOP
package.
ADM660/ADM8660 Options
Option ADM660 ADM8660
Inverting Mode Y Y
Doubling Mode Y N
External Oscillator Y N
Shutdown N Y
Package Options
SO-8 Y Y
N-8 Y Y
RU-16 Y N
REV. A
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a
CMOS Switched-Capacitor
Voltage Converters
ADM660/ADM8660
FEATURES
ADM660: Inverts or Doubles Input Supply Voltage
ADM8660: Inverts Input Supply Voltage
100 mA Output Current
Shutdown Function (ADM8660)
2.2 mF or 10 mF Capacitors
0.3 V Drop at 30 mA Load
+1.5 V to +7 V Supply
Low Power CMOS: 600 mA Quiescent Current
Selectable Charge Pump Frequency (25 kHz/120 kHz)
Pin Compatible Upgrade for MAX660, MAX665, ICL7660
Available in 16-Lead TSSOP Package
APPLICATIONS
Handheld Instruments
Portable Computers
Remote Data Acquisition
Op Amp Power Supplies
TYPICAL CIRCUIT CONFIGURATIONS
INVERTED
NEGATIVE
OUTPUT
+1.5V TO +7V
INPUT
C1
10µF
C2
10µF
ADM660
V+
GND
OUT
LV
OSC
FC
CAP+
CAP–
Voltage Inverter Configuration (ADM660)
INVERTED
NEGATIVE
OUTPUT
+1.5V TO +7V
INPUT
C1
10µF
C2
10µF
ADM8660
V+
GND
OUT
LV
FC
CAP+
CAP–
SD
SHUTDOWN
CONTROL
Voltage Inverter Configuration with Shutdown (ADM8660)
GENERAL DESCRIPTION
The ADM660/ADM8660 is a charge-pump voltage converter
that can be used to either invert the input supply voltage giving
V
OUT
= –V
IN
or double it (ADM660 only) giving V
OUT
= 2 × V
IN
.
Input voltages ranging from +1.5 V to +7 V can be inverted into
a negative –1.5 V to –7 V output supply. This inverting scheme
is ideal for generating a negative rail in single power supply
systems. Only two small external capacitors are needed for the
charge pump. Output currents up to 50 mA with greater than
90% efficiency are achievable, while 100 mA achieves greater
than 80% efficiency.
A Frequency Control (FC) input pin is used to select either
25 kHz or 120 kHz charge-pump operation. This is used to
optimize capacitor size and quiescent current. With 25 kHz
selected, a 10 µF external capacitor is suitable, while with
120 kHz the capacitor may be reduced to 2.2 µF. The oscillator
frequency on the ADM660 can also be controlled with an exter-
nal capacitor connected to the OSC input or by driving this in-
put with an external clock. In applications where a higher supply
voltage is desired it is possible to use the ADM660 to double
the input voltage. With input voltages from 2.5 V to 7 V, output
voltages from 5 V to 14 V are achievable with up to 100 mA
output current.
The ADM8660 features a low power shutdown (SD) pin in-
stead of the external oscillator (OSC) pin. This can be used to
disable the device and reduce the quiescent current to 300 nA.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
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Fax: 617/326-8703 © Analog Devices, Inc., 1997