CMOS Switched-Capacitor
Voltage Converters
ADM660/ADM8660
TYPICAL CIRCUIT CONFIGURATIONS
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
+1.5V TO +7V
INPUT
FC
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.
LV
GND
OUT
CAP–
C2
+10F
INVERTED
NEGATIVE
OUTPUT
Voltage Inverter Configuration (ADM660)
+1.5V TO +7V
INPUT
FC
ADM8660
V+
CAP+
C1 +
10F
GENERAL DESCRIPTION
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.
OSC
CAP+
C1 +
10F
APPLICATIONS
Handheld Instruments
Portable Computers
Remote Data Acquisition
Op Amp Power Supplies
The ADM660/ADM8660 is a charge-pump voltage converter
that can be used to either invert the input supply voltage giving
VOUT = –VIN or double it (ADM660 only) giving VOUT = 2 ϫ VIN.
V+
ADM660
LV
GND
OUT
CAP–
SHUTDOWN
CONTROL
C2
+10F
SD
INVERTED
NEGATIVE
OUTPUT
Voltage Inverter Configuration with Shutdown (ADM8660)
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
Doubling Mode
External Oscillator
Shutdown
Package Options
R-8
N-8
RU-16
Y
Y
Y
N
Y
N
N
Y
Y
Y
Y
Y
Y
N
REV. B
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