Precision, Micropower LDO Voltage
References in TSOT
ADR121/ADR125/ADR127
FEATURES
Initial accuracy
A grade: ±0.24%
B grade: ±0.12%
Maximum temperature coefficient
A grade: 25 ppm/°C
B grade: 9 ppm/°C
Low dropout: 300 mV for ADR121/ADR125
High output current: +5 mA/−2 mA
Low typical operating current: 85 μA
Input range: 2.7 V to 18 V for ADR127
Temperature range: −40°C to +125°C
Tiny TSOT (UJ-6) package
PIN CONFIGURATION
NC
1 1
6
NC
1
GND
2
5
NC
1
TOP VIEW
(Not to Scale)
V
IN 3
4
V
OUT
ADR12x
NC = NO CONNECT
1
MUST BE LEFT FLOATING
Figure 1.
APPLICATIONS
Battery-powered instrumentation
Portable medical equipment
Data acquisition systems
Automotive
GENERAL DESCRIPTION
The ADR121/ADR125/ADR127 are a family of micropower,
high precision, series mode, band gap references with sink and
source capability. The parts feature high accuracy and low
power consumption in a tiny package. The ADR12x design
includes a patented temperature-drift curvature correction
technique that minimizes the nonlinearities in the output
voltage vs. temperature characteristics.
The ADR12x is a low dropout voltage reference, requiring only
300 mV for the ADR121/ADR125 and 1.45 V for the ADR127
above the nominal output voltage on the input to provide a
stable output voltage. This low dropout performance, coupled
with the low 85 μA operating current, makes the ADR12x ideal
for battery-powered applications.
Available in an extended industrial temperature range of −40°C
to +125°C, the ADR121/ADR125/ADR127 are housed in the
tiny TSOT (UJ-6) package.
Rev. B
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
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
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Tel: 781.329.4700
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Fax: 781.461.3113 ©2006–2008 Analog Devices, Inc. All rights reserved.
05725-001
ADR121/ADR125/ADR127
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications ....................................................................................... 1
Pin Configuration ............................................................................. 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
ADR121 Electrical Characteristics............................................. 3
ADR125 Electrical Characteristics............................................. 4
ADR127 Electrical Characteristics............................................. 5
Absolute Maximum Ratings............................................................ 6
Thermal Resistance ...................................................................... 6
ESD Caution .................................................................................. 6
Typical Performance Characteristics ............................................. 7
Terminology .................................................................................... 15
Theory of Operation ...................................................................... 16
Power Dissipation Considerations ........................................... 16
Input Capacitor ........................................................................... 16
Output Capacitor........................................................................ 16
Applications Information .............................................................. 17
Basic Voltage Reference Connection ....................................... 17
Stacking Reference ICs for Arbitrary Outputs ....................... 17
Negative Precision Reference Without Precision Resistors .. 17
General-Purpose Current Source ............................................ 17
Outline Dimensions ....................................................................... 18
Ordering Guide .......................................................................... 18
REVISION HISTORY
1/08—Rev. A to Rev. B
Changes to Table 1 ............................................................................ 3
Changes to Table 2 ............................................................................ 4
Changes to Table 3 .............................................................................5
Changes to Figure 52 ...................................................................... 17
Changes to Ordering Guide ......................................................... 18
5/07—Rev. 0 to Rev. A
Changes to Table 1 ............................................................................ 3
Changes to Table 2 ............................................................................ 4
Changes to Table 3 ............................................................................ 5
Added Thermal Hysteresis Equation ............................................. 7
Changes to Ordering Guide .......................................................... 18
6/06—Revision 0: Initial Version
Rev. B | Page 2 of 20
ADR121/ADR125/ADR127
SPECIFICATIONS
ADR121 ELECTRICAL CHARACTERISTICS
T
A
= 25°C, V
IN
= 2.8 V to 18 V, I
OUT
= 0 mA, unless otherwise noted.
Table 1.
Parameter
OUTPUT VOLTAGE
B Grade
A Grade
INITIAL ACCURACY ERROR
B Grade
A Grade
TEMPERATURE COEFFICIENT
B Grade
A Grade
DROPOUT (V
OUT
− V
IN
)
LOAD REGULATION
Symbol
V
OUT
Conditions/Comments
Min
2.497
2.494
V
OERR
−0.12
−0.24
TCV
OUT
−40°C < T
A
< +125°C
3
15
V
DO
I
OUT
= 0 mA
−40°C < T
A
< +125°C; V
IN
= 5.0 V,
0 mA < I
OUT
< 5 mA
−40°C < T
A
< +125°C; V
IN
= 5.0 V,
−2 mA < I
OUT
< 0 mA
2.8 V to 18 V, I
OUT
= 0 mA
f = 60 Hz
−40°C < T
A
< +125°C, no load
V
IN
= 18 V
V
IN
= 2.8 V
V
IN
= 2.8 V
V
IN
= 18 V
f = 10 kHz
f = 0.1 Hz to 10 Hz
To 0.1%, C
L
= 0.2 μF
1000 hours @ 25°C
See the Terminology section
300
80
50
−50
+3
−90
95
80
18
40
500
18
100
150
300
300
300
+50
9
25
ppm/°C
ppm/°C
mV
ppm/mA
ppm/mA
ppm/V
dB
μA
μA
mA
mA
nV/√Hz
μV p-p
μs
ppm/1000 hrs
ppm
+0.12
+0.24
%
%
Typ
2.5
2.5
Max
2.503
2.506
Unit
V
V
LINE REGULATION
PSRR
QUIESCENT CURRENT
I
Q
125
95
SHORT-CIRCUIT CURRENT TO GROUND
VOLTAGE NOISE
TURN-ON SETTLING TIME
LONG-TERM STABILITY
OUTPUT VOLTAGE HYSTERESIS
Rev. B | Page 3 of 20
ADR121/ADR125/ADR127
ADR125 ELECTRICAL CHARACTERISTICS
T
A
= 25°C, V
IN
= 5.3 V to 18 V, I
OUT
= 0 mA, unless otherwise noted.
Table 2.
Parameter
OUTPUT VOLTAGE
B Grade
A Grade
INITIAL ACCURACY ERROR
B Grade
A Grade
TEMPERATURE COEFFICIENT
B Grade
A Grade
DROPOUT (V
OUT
− V
IN
)
LOAD REGULATION
Symbol
V
OUT
Conditions/Comments
Min
4.994
4.988
V
OERR
−0.12
−0.24
TCV
OUT
−40°C < T
A
< +125°C
3
15
V
DO
I
OUT
= 5 mA
−40°C < T
A
< +125°C; V
IN
= 6.0 V,
0 mA < I
OUT
< 5 mA
−40°C < T
A
< +125°C; V
IN
= 6.0 V,
−2 mA < I
OUT
< 0 mA
5.3 V to 18 V, I
OUT
= 0 mA
f = 60 Hz
−40°C < T
A
< +125°C, no load
V
IN
= 18 V
V
IN
= 5.3 V
V
IN
= 5.3 V
V
IN
= 18 V
f = 10 kHz
f = 0.1 Hz to 10 Hz
To 0.1%, C
L
= 0.2 μF
1000 hours @ 25°C
See the Terminology section
300
35
35
200
200
30
−90
95
80
25
40
900
36
100
150
300
125
95
9
25
ppm/°C
ppm/°C
mV
ppm/mA
ppm/mA
ppm/V
dB
μA
μA
mA
mA
nV/√Hz
μV p-p
μs
ppm/1000 hrs
ppm
+0.12
+0.24
%
%
Typ
5.0
5.0
Max
5.006
5.012
Unit
V
V
LINE REGULATION
PSRR
QUIESCENT CURRENT
I
Q
SHORT-CIRCUIT CURRENT TO GROUND
VOLTAGE NOISE
TURN-ON SETTLING TIME
LONG-TERM STABILITY
OUTPUT VOLTAGE HYSTERESIS
Rev. B | Page 4 of 20
ADR121/ADR125/ADR127
ADR127 ELECTRICAL CHARACTERISTICS
T
A
= 25°C, V
IN
= 2.7 V to 18 V, I
OUT
= 0 mA, unless otherwise noted.
Table 3.
Parameter
OUTPUT VOLTAGE
B Grade
A Grade
INITIAL ACCURACY ERROR
B Grade
A Grade
TEMPERATURE COEFFICIENT
B Grade
A Grade
DROPOUT (V
OUT
− V
IN
)
LOAD REGULATION
Symbol
V
OUT
Conditions/Comments
Min
1.2485
1.2470
V
OERR
−0.12
−0.24
TCV
OUT
−40°C < T
A
< +125°C
3
15
V
DO
I
OUT
= 0 mA
−40°C < T
A
< +125°C; V
IN
= 3.0 V,
0 mA < I
OUT
< 5 mA
−40°C < T
A
< +125°C; V
IN
= 3.0 V,
−2 mA < I
OUT
< 0 mA
2.7 V to 18 V, I
OUT
= 0 mA
f = 60 Hz
−40°C < T
A
< +125°C, no load
V
IN
= 18 V
V
IN
= 2.7 V
V
IN
= 2.7 V
V
IN
= 18 V
f = 10 kHz
f = 0.1 Hz to 10 Hz
To 0.1%, C
L
= 0.2 μF
1000 hours @ 25°C
See the Terminology section
1.45
85
65
30
−90
95
80
15
30
300
9
80
150
300
400
400
90
9
25
ppm/°C
ppm/°C
V
ppm/mA
ppm/mA
ppm/V
dB
μA
μA
mA
mA
nV/√Hz
μV p-p
μs
ppm/1000 hrs
ppm
+0.12
+0.24
%
%
Typ
1.25
1.25
Max
1.2515
1.2530
Unit
V
V
LINE REGULATION
PSRR
QUIESCENT CURRENT
I
Q
125
95
SHORT-CIRCUIT CURRENT TO GROUND
VOLTAGE NOISE
TURN-ON SETTLING TIME
LONG-TERM STABILITY
OUTPUT VOLTAGE HYSTERESIS
Rev. B | Page 5 of 20
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