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ADM660/ADM8660
CMOS Switched-Capacitor
Voltage Converters
FEATURES
ADM660: Inverts or Doubles Input Supply Voltage
ADM8660: Inverts Input Supply Voltage
100 mA Output Current
Shutdown Function (ADM8660)
2.2 F or 10 F Capacitors
0.3 V Drop at 30 mA Load
+1.5 V to +7 V Supply
Low Power CMOS: 600 A 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
+
+
+1.5V TO +7V
INPUT
C1
10F
C2
10F
INVERTED
NEGATIVE
OUTPUT
ADM660
FC
CAP+
GND
CAP–
V+
OSC
LV
OUT
Voltage Inverter Configuration (ADM660)
+
+
+1.5V TO +7V
INPUT
C1
10F
C2
10F
INVERTED
NEGATIVE
OUTPUT
ADM8660
FC
CAP+
GND
CAP–
V+
LV
OUT
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 external capacitor
connected to the OSC input or by driving this input 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 instead
of the external oscillator (OSC) pin. This can be used to disable
the device and reduce the quiescent current to 300 nA.
The ADM660 is a pin compatible upgrade for the MAX660,
MAX665, ICL7660, and LTC1046.
The ADM660/ADM8660 is available in 8-lead 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
R-8 Y Y
N-8 Y Y
RU-16 Y N
