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a
Tri-Mode: +3.3 V, +5 V, Adjustable
Micropower Linear Voltage Regulators
ADM663A/ADM666A*
FEATURES
Tri-Mode Operation
3.3 V, 5 V Fixed or +1.3 V to +16 V Adjustable
Low Power CMOS: 9 µA max Quiescent Current
High Current 100 mA Output
Low Dropout Voltage
Upgrade for ADM663/ADM666
“Small” 0.1 µF Output Capacitor (0805 Style)
+2 V to +16.5 V Operating Range
Low Battery Detector ADM666A
No Overshoot on Power-Up
Thermal Shutdown
APPLICATIONS
Handheld Instruments
LCD Display Systems
Pagers
Battery Operated Equipment
GENERAL DESCRIPTION
The ADM663A/ADM666A are precision linear voltage regula-
tors featuring a maximum quiescent current of 9 µA. They can
be used to give a fixed +3.3 V or +5 V output with no additional
external components or can be adjusted from 1.3 V to 16 V
using two external resistors. Fixed or adjustable operation is au-
tomatically selected via the V
SET
input. The low quiescent cur-
rent makes these devices especially suitable for battery powered
systems. The input voltage range is 2 V to 16.5 V, and an out-
put current up to 100 mA is provided. Current limiting may be
set using a single external resistor. For additional safety, an
internal thermal shutdown circuit monitors the internal die
temperature.
The ADM666A features additional low battery monitoring cir-
cuitry to detect for low battery voltages.
The ADM663A/ADM666A are pin compatible enhancements
for the ADM663/ADM666. Improvements include an addi-
tional 3.3 V output range, higher output current, and operation
with a small output capacitor.
The ADM663A/ADM666A are available in an 8-pin DIP and
narrow surface mount (SOIC) packages.
*Patent pending.
FUNCTIONAL BLOCK DIAGRAMS
50mV
V
IN
ADM663A
SHDN
GND
V
TC
V
SET
V
OUT1
V
OUT2
SENSE
C2
1.3V
0.5V
C1
A2
A1
C3
D
E
C
O
D
E
R
V
IN
–50mV
0.9V
R2
R1
R3
50mV
V
IN
ADM666A
SHDN
GND
LBO
V
SET
V
OUT
SENSE
C2
1.3V
0.5V
C1
C4
A1
C3
D
E
C
O
D
E
R
V
IN
–50mV
1.3 V
LBI
R2
R1
R3