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use, nor for any infringements of patents or other rights of third parties
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a
ADP1110
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
World Wide Web Site: http://www.analog.com
Fax: 617/326-8703
Analog Devices, Inc., 1996
Micropower, Step-Up/Step-Down Switching
Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 V
FUNCTIONAL BLOCK DIAGRAMS
SENSE
A0
DRIVER
I
LIM
SW1
SW2
V
IN
SET
220mV
REFERENCE
GAIN BLOCK/
ERROR AMP
A2
A1
Q1
OSCILLATOR
ADP1110
GND
COMPARATOR
R2
300k
R1
ADP1110 Block Diagram—Fixed Output Version
A0
DRIVER
I
LIM
SW1
SW2
V
IN
GND
SET
220mV
REFERENCE
GAIN BLOCK/
ERROR AMP
COMPARATOR
FB
A2
A1
Q1
OSCILLATOR
ADP1110
ADP1110 Block Diagram—Adjustable Output Version
The 70 kHz frequency operation also allows for the use of
surface-mount external capacitors and inductors.
Battery protection circuitry limits the effect of reverse current to
safe levels at reverse voltages up to 1.6 V.
FEATURES
Operates at Supply Voltages From 1.0 V to 30 V
Step-Up or Step-Down Mode
Minimal External Components Required
Low-Battery Detector
User-Adjustable Current Limiting
Fixed or Adjustable Output Voltage Versions
8-Pin DIP or SO-8 Package
APPLICATIONS
Cellular Telephones
Single-Cell to 5 V Converters
Laptop and Palmtop Computers
Pagers
Cameras
Battery Backup Supplies
Portable Instruments
Laser Diode Drivers
Hand-Held Inventory Computers
GENERAL DESCRIPTION
The ADP1110 is part of a family of step-up/step-down switch-
ing regulators that operate from an input voltage supply as little
as 1.0 V. This very low input voltage allows the ADP1110 to be
used in applications that use a single cell as the primary power
source.
The ADP1110 can be configured to operate in either step-up or
step-down mode, but for input voltages greater than 3 V, the
ADP1111 would be a more effective solution.
An auxiliary gain amplifier can serve as a low battery detector or
as a linear regulator.
The quiescent current of 300
μ
A makes the ADP1110 useful in
remote or battery powered applications.