5.5 V Input, 300 mA, Low Quiescent
Current, CMOS Linear Regulator
Data Sheet
ADP122/ADP123
FEATURES
TYPICAL APPLICATION CIRCUITS
Input voltage supply range: 2.3 V to 5.5 V
300 mA maximum output current
Fixed and adjustable output voltage versions
Very low dropout voltage: 85 mV at 300 mA load
Low quiescent current: 45 µA at no load
Low shutdown current: <1 µA
V
= 2.3V TO 5.5V
V
= 1.8V
IN
OUT
1
5
VIN
VOUT
C
C
IN
OUT
1µF
ADP122
1µF
2
3
GND
ON
4
EN
NC
OFF
Initial accuracy: 1% accuracy
Figure 1. ADP122 with Fixed Output Voltage (TSOT Version)
Up to 31 fixed-output voltage options available from
1.75 V to 3.3 V
V
= 2.3V TO 5.5V
V
= 0.5V(1 + R1/R2)
IN
OUT
Adjustable-output voltage range
0.8 V to 5.0 V (ADP123)
1
5
VIN
VOUT
C
1µF
C
IN
OUT
1µF
ADP123
R1
Excellent PSRR performance: 60 dB at 100 kHz
Excellent load/line transient response
Optimized for small 1.0 μF ceramic capacitors
Current limit and thermal overload protection
Logic controlled enable
2
3
GND
ON
4
EN
ADJ
OFF
R2
Compact packages: 5-lead TSOT and 6-lead 2 mm × 2 mm LFCSP
Figure 2. ADP123 with Adjustable Output Voltage (TSOT Version)
APPLICATIONS
VOUT = 1.8V
VIN = 2.3V TO 5.5V
1
6
VOUT
NC
VIN
NC
EN
C1
1µF
C2
1µF
Digital camera and audio devices
Portable and battery-powered equipment
Automatic meter reading (AMR) meters
GPS and location management units
Medical instrumentation
2
3
5
4
GND
GND
ON
GND
OFF
GND
ADP122
TOP VIEW
(Not to Scale)
Point-of-sale equipment
NC = NOT CONNECT. THIS PIN CAN BE LEFT FLOATING
OR CONNECTED TO GROUND.
GENERAL DESCRIPTION
The ADP122/ADP123 are low quiescent current, low dropout
linear regulators. They are designed to operate from an input
voltage between 2.3 V and 5.5 V and to provide up to 300 mA of
output current. The low 85 mV dropout voltage at a 300 mA load
improves efficiency and allows operation over a wide input
voltage range.
Figure 3. ADP122 with Fixed Output Voltage (LFCSP Version)
VOUT = 0.5V (1 + R1/R2)
VIN = 2.3V TO 5.5V
1
2
3
6
VOUT
ADJ
VIN
NC
EN
C1
1µF
C2
1µF
R1
5
4
GND
GND
R2
ON
GND
GND
OFF
GND
ADP123
TOP VIEW
(Not to Scale)
The low 170 μA of quiescent current at full load makes the ADP122
ideal for battery-operated portable equipment.
NC = NOT CONNECT. THIS PIN CAN BE LEFT FLOATING
OR CONNECTED TO GROUND.
The ADP122 is capable of 31 fixed output voltages from 1.75 V
to 3.3 V. The ADP123 is the adjustable version of the device and
allows the output voltage to be set between 0.8 V and 5.0 V by
an external voltage divider.
Figure 4. ADP123 with Adjustable Output Voltage (LFCSP Version)
The ADP122/ADP123 have an internal soft start that gives a
constant start-up time of 350 µs. Short-circuit protection and
thermal overload protection circuits prevent damage in adverse
conditions. The ADP122/ADP123 are available in a tiny, 5-lead
TSOT package and 6-lead LFCSP package for the smallest
footprint solution to meet a variety of portable applications.
The ADP122/ADP123 are specifically designed for stable operation
with tiny 1 µF ceramic input and output capacitors to meet the
requirements of high performance, space constrained applications.
Rev. E
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rightsof third parties that may result fromits use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks andregisteredtrademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113 ©2009–2012 Analog Devices, Inc. All rights reserved.