Micropower Step-Up/Step-Down
Fixed 3.3 V, 5 V, 12 V and Adjustable
High Frequency Switching Regulator
a
ADP3000
FUNCTIONAL BLOCK DIAGRAM
FEATURES
Operates at Supply Voltages from 2 V to 30 V
Works in Step-Up or Step-Down Mode
Very Few External Components Required
High Frequency Operation Up to 400 kHz
Low Battery Detector on Chip
User Adjustable Current Limit
Fixed and Adjustable Output Voltage
8-Pin DIP and SO-8 Package
SET
A1
A0
V
IN
I
GAIN BLOCK/
ERROR AMP
LIM
SW1
1.245V
REFERENCE
400kHz
OSCILLATOR
Small Inductors and Capacitors
DRIVER
SW2
COMPARATOR
APPLICATIONS
ADP3000
Notebook, Palmtop Computers
Cellular Telephones
Hard Disk Drives
R1
R2
GND
SENSE
Portable Instruments
Pagers
6.8µH
IN5817
V
IN
3.3V @
180mA
2V–3.2V
100µF
10V
120Ω
GENERAL DESCRIPTION
1
2
The ADP3000 is a versatile step-up/step-down switching
regulator that operates from an input supply voltage of 2 V to
12 V in step-up mode and up to 30 V in step-down mode.
I
V
LIM
IN
SW1
3
8
ADP3000-3.3V
The ADP3000 operates in Pulse Frequency Mode (PFM) and
consumes only 500 µA, making it highly suitable for applica-
tions that require low quiescent current.
FB
(SENSE)
C1
100µF
10V
+
GND
5
SW2
4
The ADP3000 can deliver an output current of 100 mA at
3 V from a 5 V input in step-down configuration and 180 mA at
3.3 V from a 2 V input in step-up configuration.
C1, C2: AVX TPS D107 M010R0100
L1: SUMIDA CD43-6R8
The auxiliary gain amplifier can be used as a low battery detector,
linear regulator undervoltage lockout or error amplifier.
Figure 1. Typical Application
The ADP3000 operates at 400 kHz switching frequency. This
allows the use of small external components (inductors and
capacitors), making the device very suitable for space constrained
designs.
V
IN
R
120Ω
5V–6V
C1
100µF
10V
LIM
1
2
3
I
V
SW1
LIM
IN
8
4
FB
ADP3000
L1
10µH
V
SW2
OUT
R2
GND
5
3V
100mA
150kΩ
1%
CL
100µF
10V
+
D1
1N5818
R1
110kΩ
1%
C1, C2: AVX TPS D107 M010R0100
L1: SUMIDA CD43-100
Figure 2. Step-Down Mode Operation
REV. 0
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reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
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Tel: 617/329-4700
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© Analog Devices, Inc., 1997