Micropower, Low Noise Precision Voltage
References with Shutdown
ADR390/ADR391/ADR392/ADR395
Rev. F
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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
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Tel: 781.329.4700
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Fax: 781.461.3113
© 2005 Analog Devices, Inc. All rights reserved.
FEATURES
Compact TSOT-23-5 packages
Low temperature coefficient
B grade: 9 ppm/°C
A grade: 25 ppm/°C
Initial accuracy
B grade: ±4 mV maximum
A grade: ±6 mV maximum
Ultralow output noise: 5 µV p-p (0.1 Hz to 10 Hz)
Low dropout: 300 mV
Low supply current
3 µA maximum in shutdown
120 µA maximum in operation
No external capacitor required
Output current: 5 mA
Wide temperature range
-40°C to + 125°C
APPLICATIONS
Battery-powered instrumentation
Portable medical instrumentation
Data acquisition systems
Industrial process controls
Automotive
FUNCTIONAL BLOCK DIAGRAM
1
2
3
ADR390/
ADR391/
ADR392/
ADR395
5
4
SHDN
V
IN
V
OUT (SENSE)
GND
V
OUT (FORCE)
(Not to Scale)
00419-D-001
Figure 1. 5-Lead TSOT (UJ Suffix)
Table 1.
Model V
OUT
(V)
Temperature
Coefficient (ppm/°C)
Accuracy (mV)
ADR390B 2.048 9
±4
ADR390A 2.048 25
±6
ADR391B 2.5
9
±4
ADR391A 2.5
25
±6
ADR392B 4.096 9
±5
ADR392A 4.096 25
±6
ADR395B 5.0
9
±5
ADR395A 5.0
25
±6
GENERAL DESCRIPTION
The ADR390, ADR391, ADR392, and ADR395 are precision
2.048 V, 2.5 V, 4.096 V, and 5 V band gap voltage references,
respectively, featuring low power and high precision in a tiny
footprint. Using ADI's patented temperature drift curvature
correction techniques, the ADR39x references achieve a low
9 ppm/°C of temperature drift in the TSOT package.
The ADR39x family of micropower, low dropout voltage
references provides a stable output voltage from a minimum
supply of 300 mV above the output. Their advanced design
eliminates the need for external capacitors, which further
reduces board space and system cost. The combination of
low power operation, small size, and ease of use makes the
ADR39x precision voltage references ideally suited for battery-
operated applications.
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 2 of 20
TABLE OF CONTENTS
ADR390 Specifications .................................................................... 3
ADR391 Specifications .................................................................... 4
ADR392 Specifications .................................................................... 5
ADR395 Specifications .................................................................... 6
Absolute Maximum Ratings............................................................ 7
Thermal Resistance ...................................................................... 7
ESD Caution.................................................................................. 7
Terminology .......................................................................................8
Typical Performance Characteristics ..............................................9
Theory of Operation ...................................................................... 16
Applications..................................................................................... 17
Basic Voltage Reference Connection ....................................... 17
Outline Dimensions ....................................................................... 19
Ordering Guide .......................................................................... 19
REVISION HISTORY
5/05--Rev. E to Rev. F
Changes to Table 5........................................................................... 7
Changes to Figure 2......................................................................... 9
4/04--Rev. D to Rev. E
Changes to ADR390--Specifications............................................ 3
Changes to ADR391--Specifications............................................ 4
Changes to ADR392--Specifications............................................ 5
Changes to ADR395--Specifications............................................ 6
4/04--Rev. C to Rev. D
Updated Format................................................................ Universal
Changes to Title ............................................................................... 1
Changes to Features......................................................................... 1
Changes to Applications ................................................................. 1
Changes to General Description ................................................... 1
Changes to Table 1........................................................................... 1
Changes to ADR390--Specifications............................................ 3
Changes to ADR391--Specifications............................................ 4
Changes to ADR392--Specifications............................................ 5
Changes to ADR395--Specifications............................................ 6
Changes to Absolute Maximum Ratings ...................................... 7
Changes to Thermal Resistance..................................................... 7
Moved ESD Caution........................................................................ 7
Changes to Figure 3, Figure 4, Figure 7, and Figure 8 ................ 9
Changes to Figure 11, Figure 12, Figure 13, and Figure 14...... 10
Changes to Figure 15, Figure 16, Figure 19, and Figure 20...... 11
Changes to Figure 23 and Figure 24............................................ 12
Changes to Figure 27..................................................................... 13
Changes to Ordering Guide ......................................................... 19
Updated Outline Dimensions...................................................... 19
10/02--Rev. B to Rev. C
Add parts ADR392 and ADR395 ....................................Universal
Changes to Features ........................................................................ 1
Changes to General Description ................................................... 1
Additions to Table I......................................................................... 1
Changes to Specifications............................................................... 2
Changes to Ordering Guide ........................................................... 4
Changes to Absolute Maximum Ratings...................................... 4
New TPCs 3, 4, 7, 8, 11, 12, 15, 16, 19, and 20 ............................ 6
New Figures 4 and 5...................................................................... 13
Deleted A Negative Precision Reference
without Precision Resistors Section ............................................ 13
Edits to General-Purpose Current Source Section ................... 13
Updated Outline Dimensions...................................................... 15
5/02--Rev. A to Rev. B
Edits to Layout ...................................................................Universal
Changes to Figure 6....................................................................... 13
Revision 0: Initial Version
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 3 of 20
ADR390 SPECIFICATIONS
Electrical characteristics, V
IN
= 2.5 V to 15 V, T
A
= 25°C, unless otherwise noted.
Table 2.
Parameter Symbol
Conditions
Min
Typ
Max
Unit
OUTPUT VOLTAGE
V
O
A
grade
2.042 2.048 2.054 V
V
O
B
grade
2.044 2.048 2.052 V
INITIAL ACCURACY
V
OERR
A grade
6
mV
V
OERR
A
grade
0.29
%
V
OERR
B
grade
4
mV
V
OERR
B
grade
0.19
%
A grade: -40°C < T
A
< +125°C
25
ppm/°C
TEMPERATURE COEFFICIENT
TCV
O
B grade: -40°C < T
A
< +125°C
9
ppm/°C
SUPPLY VOLTAGE HEADROOM
V
IN
- V
O
300
mV
LINE REGULATION
V
O
/V
IN
V
IN
= 2.5 V to 15 V, -40°C < T
A
<
+125°C
10 25 ppm/V
I
LOAD
= 0 mA to 5 mA, -40°C < T
A
< +85°C, V
IN
= 3 V
60
ppm/mA
LOAD REGULATION
V
O
/I
LOAD
I
LOAD
= 0 mA to 5 mA, -40°C < T
A
< +125°C, V
IN
= 3 V
140
ppm/mA
No load
120
µA
QUIESCENT CURRENT
I
IN
-40°C < T
A
< +125°C
140
µA
VOLTAGE NOISE
en
p-p
0.1 Hz to 10 Hz
5
µV p-p
TURN-ON SETTLING TIME
t
R
20
µs
LONG-TERM STABILITY
1
V
O
1000
hours
50
ppm
OUTPUT VOLTAGE HYSTERESIS
V
O_HYS
100
ppm
RIPPLE REJECTION RATIO
RRR
f
IN
= 60 kHz
80
dB
V
IN
= 5 V
25
mA
SHORT CIRCUIT TO GND
I
SC
V
IN
= 15 V
30
mA
SHUTDOWN
PIN
Shutdown Supply Current
I
SHDN
3
µA
Shutdown Logic Input Current
I
LOGIC
500
nA
Shutdown Logic Low
V
INL
0.8
V
Shutdown Logic High
V
INH
2.4
V
1
The long-term stability specification is noncumulative. The drift of subsequent 1000 hour periods is significantly lower than in the first 1000 hour period.
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 4 of 20
ADR391 SPECIFICATIONS
Electrical characteristics, V
IN
= 2.8 V to 15 V, T
A
= 25°C, unless otherwise noted.
Table 3.
Parameter Symbol
Conditions
Min
Typ
Max
Unit
OUTPUT VOLTAGE
V
O
A
grade
2.494 2.5 2.506 V
V
O
B
grade
2.496 2.5 2.504 V
V
OERR
A
grade
6
mV
INITIAL ACCURACY
V
OERR
A
grade
0.24
%
V
OERR
B
grade
4
mV
V
OERR
B
grade
0.16
%
A grade, -40°C < T
A
< +125°C
25
ppm/°C
TEMPERATURE COEFFICIENT
TCV
O
B grade, -40°C < T
A
< +125°C
9
ppm/°C
SUPPLY VOLTAGE HEADROOM
V
IN
- V
O
300
mV
LINE REGULATION
V
O
/V
IN
V
IN
= 2.8 V to 15 V, -40°C < T
A
< +125°C
10
25
ppm/V
I
LOAD
= 0 mA to 5 mA, -40°C < T
A
< +85°C, V
IN
= 3 V
60
ppm/mA
LOAD REGULATION
V
O
/I
LOAD
I
LOAD
= 0 mA to 5 mA, -40°C < T
A
< +125°C, V
IN
= 3 V
140
ppm/mA
No load
120
µA
QUIESCENT CURRENT
I
IN
-40°C < T
A
< +125°C
140
µA
VOLTAGE NOISE
en
p-p
0.1 Hz to 10 Hz
5
µV p-p
TURN-ON SETTLING TIME
t
R
20
µs
LONG-TERM STABILITY
1
V
O
1000
hours
50
ppm
OUTPUT VOLTAGE HYSTERESIS
V
O_HYS
100
ppm
RIPPLE REJECTION RATIO
RRR
f
IN
= 60 kHz
80
dB
V
IN
= 5 V
25
mA
SHORT CIRCUIT TO GND
I
SC
V
IN
= 15 V
30
mA
SHUTDOWN
PIN
Shutdown Supply Current
I
SHDN
3
µA
Shutdown Logic Input Current
I
LOGIC
500
nA
Shutdown Logic Low
V
INL
0.8
V
Shutdown Logic High
V
INH
2.4
V
1
The long-term stability specification is noncumulative. The drift of subsequent 1000 hour periods is significantly lower than in the first 1000 hour period.
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 5 of 20
ADR392 SPECIFICATIONS
Electrical characteristics, V
IN
= 4.3 V to 15 V, T
A
= 25°C, unless otherwise noted.
Table 4.
Parameter Symbol
Conditions
Min
Typ
Max
Unit
OUTPUT VOLTAGE
V
O
A
grade
4.090 4.096 4.102 V
V
O
B
grade
4.091 4.096 4.101 V
V
OERR
A
grade
6
mV
INITIAL ACCURACY
V
OERR
A
grade
0.15
%
V
OERR
B
grade
5
mV
V
OERR
B
grade
0.12
%
A grade, -40°C < T
A
< +125°C
25
ppm/°C
TEMPERATURE COEFFICIENT
TCV
O
B grade, -40°C < T
A
< +125°C
9
ppm/°C
SUPPLY VOLTAGE HEADROOM
V
IN
- V
O
300
mV
LINE REGULATION
V
O
/V
IN
V
IN
= 4.3 V to 15 V, -40°C < T
A
<
+125°C
10 25 ppm/V
LOAD REGULATION
V
O
/I
LOAD
I
LOAD
= 0 mA to 5 mA, -40°C < T
A
< +125°C, V
IN
= 5 V
140
ppm/mA
No load
120
µA
QUIESCENT CURRENT
I
IN
-40°C < T
A
< +125°C
140
µA
VOLTAGE NOISE
en
p-p
0.1 Hz to 10 Hz
7
µV p-p
TURN-ON SETTLING TIME
t
R
20
µs
LONG-TERM STABILITY
1
V
O
1000
hours
50
ppm
OUTPUT VOLTAGE HYSTERESIS
V
O_HYS
100
ppm
RIPPLE REJECTION RATIO
RRR
f
IN
= 60 kHz
80
dB
V
IN
= 5 V
25
mA
SHORT CIRCUIT TO GND
I
SC
V
IN
= 15 V
30
mA
SHUTDOWN
PIN
Shutdown Supply Current
I
SHDN
3
µA
Shutdown Logic Input Current
I
LOGIC
500
nA
Shutdown Logic Low
V
INL
0.8
V
Shutdown Logic High
V
INH
2.4
V
1
The long-term stability specification is noncumulative. The drift of subsequent 1000 hour periods is significantly lower than in the first 1000 hour period.
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 6 of 20
ADR395 SPECIFICATIONS
Electrical characteristics, V
IN
= 5.3 V to 15 V, T
A
= 25°C, unless otherwise noted.
Table 5.
Parameter Symbol
Conditions
Min
Typ
Max
Unit
OUTPUT VOLTAGE
V
O
A
grade
4.994 5.000 5.006 V
V
O
B
grade
4.995 5.000 5.005 V
V
OERR
A
grade
6
mV
INITIAL ACCURACY
V
OERR
B
grade
0.12
%
V
OERR
B
grade
5
mV
V
OERR
B
grade
0.10
%
A grade, -40°C < T
A
< +125°C
25
ppm/°C
TEMPERATURE COEFFICIENT
TCV
O
B grade, -40°C < T
A
< +125°C
9
ppm/°C
SUPPLY VOLTAGE HEADROOM
V
IN
- V
O
300
mV
LINE REGULATION
V
O
/V
IN
V
IN
= 4.3 V to 15 V, -40°C < T
A
< +125°C
10
25
ppm/V
LOAD REGULATION
V
O
/I
LOAD
I
LOAD
= 0 mA to 5 mA, -40°C < T
A
< +125°C, V
IN
= 6 V
140
ppm/mA
No load
120
µA
QUIESCENT CURRENT
I
IN
-40°C < T
A
< +125°C
140
µA
VOLTAGE NOISE
en
p-p
0.1 Hz to 10 Hz
8
µV p-p
TURN-ON SETTLING TIME
t
R
20
µs
LONG-TERM STABILITY
1
V
O
1, 000 hours
50
ppm
OUTPUT VOLTAGE HYSTERESIS
V
O_HYS
100
ppm
RIPPLE REJECTION RATIO
RRR
f
IN
= 60 kHz
80
dB
V
IN
= 5 V
25
mA
SHORT CIRCUIT TO GND
I
SC
V
IN
= 15 V
30
mA
SHUTDOWN
PIN
Shutdown Supply Current
I
SHDN
3
µA
Shutdown Logic Input Current
I
LOGIC
500
nA
Shutdown Logic Low
V
INL
0.8
V
Shutdown Logic High
V
INH
2.4
V
1
The long-term stability specification is noncumulative. The drift of subsequent 1,000 hour periods is significantly lower than in the first 1,000 hour period.
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 7 of 20
ABSOLUTE MAXIMUM RATINGS
At 25°C, unless otherwise noted.
Table 6.
Parameter Rating
Supply Voltage
18 V
Output Short-Circuit Duration to GND
See derating
curves
Storage Temperature Range
65°C to +125°C
Operating Temperature Range
40°C to +125°C
Junction Temperature Range
65°C to +125°C
Lead Temperature Range
(Soldering, 60 sec)
300°C
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only and functional operation of the device at these or
any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
THERMAL RESISTANCE
JA
is specified for the worst-case conditions, that is,
JA
is
specified for a device soldered in a circuit board for surface-
mount packages.
Table 7. Thermal Resistance
Package Type
JA
JC
Unit
TSOT-23-5 (UJ-5)
230
146
°C/W
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the
human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 8 of 20
TERMINOLOGY
Temperature Coefficient
The change of output voltage with respect to operating temp-
erature changes normalized by the output voltage at 25°C. This
parameter is expressed in ppm/°C and can be determined by the
following equation:
[
]
( )
( )
(
)
(
)
6
10
25
×
×
°
=
°
1
2
O
1
O
2
O
O
T
T
C
V
T
V
T
V
C
/
ppm
TCV
where:
V
O
(25°C) = V
O
at 25°C
V
O
(T
1
) = V
O
at Temperature 1
V
O
(T
2
) = V
O
at Temperature 2
Line Regulation
The change in output voltage due to a specified change in input
voltage. This parameter accounts for the effects of self-heating.
Line regulation is expressed in either percent per volt, parts-
per-million per volt, or microvolts per volt change in input
voltage.
Load Regulation
The change in output voltage due to a specified change in load
current. This parameter accounts for the effects of self-heating.
Load regulation is expressed in either microvolts per milli-
ampere, parts-per-million per milliampere, or ohms of dc
output resistance.
Long-Term Stability
Typical shift of output voltage at 25°C on a sample of parts
subjected to a test of 1,000 hours at 25°C.
V
O
= V
O
(t
0
) V
O
(t
1
)
[
]
( )
( )
( )
×
=
6
10
0
O
1
O
0
O
O
t
V
t
V
t
V
ppm
V
where:
V
O
(T
0
) = V
O
at 25°C at Time 0
V
O
(T
1
) = V
O
at 25°C after 1,000 hours operation at 25°C
Thermal Hysteresis
The change of output voltage after the device is cycled through
temperatures from +25°C to 40°C to +125°C and back to
+25°C. This is a typical value from a sample of parts put
through such a cycle.
V
O_HYS
= V
O
(25°C) V
O_TC
[
]
(
)
(
)
6
10
25
25
×
°
°
=
C
V
V
C
V
ppm
V
O
O_TC
O
O_HYS
where:
V
O
(25°C) = V
O
at 25°C
V
O_TC
= V
O
at 25°C after a temperature cycle from + 25°C
to 40°C to +125°C and back to +25°C
NOTES
Input Capacitor
Input capacitors are not required on the ADR39x. There is no
limit for the value of the capacitor used on the input, but a
1 µF to 10 µF capacitor on the input improves transient
response in applications where the supply suddenly changes.
An additional 0.1 µF in parallel also helps reduce noise
from the supply.
Output Capacitor
The ADR39x does not require output capacitors for stability
under any load condition. An output capacitor, typically 0.1 µF,
filters out any low level noise voltage and does not affect the
operation of the part. On the other hand, the load transient
response can improve with the addition of a 1 µF to 10 µF
output capacitor in parallel. A capacitor here acts as a source of
stored energy for a sudden increase in load current. The only
parameter that degrades by adding an output capacitor is the
turn-on time, and it depends on the size of the capacitor
chosen.
150
DRIFT (ppm)
150
TIME (Hours)
0
100
50
0
50
100
100
200
300
400
500
600
700
1000
00419-D-002
900
800
Figure 2. ADR391 Typical Long-Term Drift over 1,000 Hours
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 9 of 20
TYPICAL PERFORMANCE CHARACTERISTICS
TEMPERATURE (
°
C)
2.040
40
5
OUTPUT VOLTAGE
(V
)
30
65
100
125
2.044
2.048
2.052
2.056
2.060
SAMPLE 3
SAMPLE 2
SAMPLE 1
00419-D-003
Figure 3. ADR390 Output Voltage vs. Temperature
2.494
40
5
V
OUT
(V
)
30
65
100
125
2.496
2.498
2.500
2.502
2.504
2.506
SAMPLE 1
SAMPLE 2
SAMPLE 3
00419-D-004
TEMPERATURE (
°
C)
Figure 4. ADR391 Output Voltage vs. Temperature
TEMPERATURE (
°
C)
4.100
40
0
40
80
125
V
OUT
(V
)
4.098
4.096
4.094
4.090
4.088
4.092
SAMPLE 1
SAMPLE 2
SAMPLE 3
00419-D-005
Figure 5. ADR392 Output Voltage vs. Temperature
5.006
40
5
30
65
125
V
OUT
(V
)
5.004
5.002
5.000
4.996
4.994
4.998
100
SAMPLE 1
SAMPLE 2
SAMPLE 3
00419-D-006
TEMPERATURE (
°
C)
Figure 6. ADR395 Output Voltage vs. Temperature
INPUT VOLTAGE (V)
140
120
40
2.5
15.0
5.0
S
U
P
P
L
Y
CURRE
NT (
µ
A)
7.5
10.0
12.5
100
80
60
+125
°
C
+25
°
C
40
°
C
00419-D-007
+85
°
C
Figure 7. ADR390 Supply Current vs. Input Voltage
INPUT VOLTAGE (V)
140
120
40
2.5
15.0
5.0
S
U
P
P
L
Y
CURRE
NT (
µ
A)
7.5
10.0
12.5
100
80
60
+85
°
C
+25
°
C
40
°
C
00419-D-008
Figure 8. ADR391 Supply Current vs. Input Voltage
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 10 of 20
INPUT VOLTAGE (V)
140
5
7
9
11
15
S
U
P
P
L
Y
CURRE
NT (
µ
A)
120
100
60
40
80
13
+125
°
C
+25
°
C
40
°
C
00419-D-009
Figure 9. ADR392 Supply Current vs. Input Voltage
INPUT VOLTAGE (V)
140
5.5
7.0
8.5
10.0
14.5
S
U
P
P
L
Y
CURRE
NT (
µ
A)
120
100
60
40
80
13.0
+125
°
C
+25
°
C
40
°
C
11.5
00419-D-010
Figure 10. ADR395 Supply Current vs. Input Voltage
TEMPERATURE (
°
C)
0
40
10
LOAD REGULATION (ppm/mA)
20
50
80
125
20
40
60
80
100
120
00419-D-011
110
V
IN
= 3.0V
V
IN
= 5.0V
I
L
= 0mA TO 5mA
Figure 11. ADR390 Load Regulation vs. Temperature
TEMPERATURE (
°
C)
80
40
10
LOAD RE
GULATION (ppm/mA)
50
80
110
125
100
120
140
160
180
00419-D-012
V
IN
= 5.0V
V
IN
= 3.0V
I
L
= 0mA TO 5mA
20
Figure 12. ADR391 Load Regulation vs. Temperature
TEMPERATURE (
°
C)
90
40
5
30
65
125
LOAD REGULATION (ppm/mA)
80
70
50
40
60
V
IN
= 7.5V
100
V
IN
= 5V
00419-D-013
I
L
= 0mA TO 5mA
Figure 13. ADR392 Load Regulation vs. Temperature
TEMPERATURE (
°
C)
80
40
5
30
65
125
LO
AD REGULA
TION (ppm/mA)
70
60
40
30
50
V
IN
= 7.5V
100
V
IN
= 5V
00419-D-014
I
L
= 0mA TO 5mA
Figure 14. ADR395 Load Regulation vs. Temperature
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 11 of 20
TEMPERATURE (
°
C)
0
40
10
LINE REGULATION (ppm/V)
20
80
110
125
25
5
10
15
20
00419-D-015
50
Figure 15. ADR390 Line Regulation vs. Temperature
TEMPERATURE (
°
C)
0
LINE REGULATION (ppm/V)
25
5
10
15
20
00419-D-016
40
10
20
80
110 125
50
Figure 16. ADR391 Line Regulation vs. Temperature
TEMPERATURE
(
°
C)
14
40
5
30
65
125
LINE REGULA
TION (ppm/V)
10
6
2
0
4
100
12
8
V
IN
= 4.4V TO 15V
00419-D-017
Figure 17. ADR392 Line Regulation vs. Temperature
TEMPERATURE
(
°
C)
14
40
5
30
65
125
LINE REGULA
TION (ppm/V)
10
6
2
0
4
100
12
8
V
IN
= 5.3V TO 15V
00419-D-018
Figure 18. ADR395 Line Regulation vs. Temperature
LOAD CURRENT (mA)
3.0
2.0
0
1
V
I
N_
MIN (V
)
2
3
4
2.6
2.4
2.2
40
°
C
+85
°
C
+25
°
C
00419-D-019
5
2.8
+125
°
C
Figure 19. ADR390 Minimum Input Voltage vs. Load Current
LOAD CURRENT (mA)
3.6
2.6
0
1
3.4
3.2
2.8
40
°
C
+85
°
C
+25
°
C
V
I
N_
MIN (V
)
00419-D-020
2
3
4
5
3.0
+125
°
C
Figure 20. ADR391 Minimum Input Voltage vs. Load Current
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 12 of 20
LOAD CURRENT (mA)
4.8
0
1
2
3
5
V
I
N_
MIN (V
) 4.4
4.0
3.8
4.2
4
4.6
+125
°
C
+25
°
C
40
°
C
00419-D-021
Figure 21. ADR392 Minimum Input Voltage vs. Load Current
LOAD CURRENT (mA)
6.0
0
1
2
3
5
V
I
N_
MIN (V
)
5.2
4.8
4.6
5.0
4
5.6
+125
°
C
+25
°
C
40
°
C
5.8
5.4
00419-D-022
Figure 22. ADR395 Minimum Input Voltage vs. Load Current
V
OUT
DEVIATION (mV)
60
50
0
0.24
0.30
0.12
FRE
Q
UE
NCY
0
0.06
0.18
40
30
20
10
0.18
0.06
0.12
0.24
00419-D-023
TEMPERATURE: +25
°
C
40
°
C
+125
°
C
+25
°
C
Figure 23. ADR390 V
OUT
Hysteresis Distribution
V
OUT
DEVIATION (mV)
70
50
0
0.56
0.26
FRE
Q
UE
NCY
0.04
0.19
40
30
20
10
0.41
0.11
0.34
60
TEMPERATURE: +25
°
C
40
°
C
+125
°
C
+25
°
C
00419-D-024
Figure 24. ADR391 V
OUT
Hysteresis Distribution
FREQUENCY (Hz)
1k
100
10
10k
100
VOLTA
GE N
O
ISE D
E
N
S
ITY (
n
V/ H
z
)
1k
ADR390
ADR391
V
IN
= 5V
00419-D-025
Figure 25. Voltage Noise Density vs. Frequency
VOLTAGE (2
µ
V/D
I
V)
TIME (1 Sec/DIV)
0
0
0
0
0
0
0
0
0
00419-D-026
Figure 26. ADR391 Typical Voltage Noise 0.1 Hz to 10 Hz
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 13 of 20
VOLTAGE (100
µ
V/D
I
V)
TIME (10
µ
s/DIV)
Figure 27. ADR391 Voltage Noise 10 Hz to 10 kHz
VOLTAGE
TIME (10
µ
s/DIV)
C
BYPASS
= 0
µ
F
LINE
INTERRUPTION
V
OUT
0.5V/DIV
1V/DIV
00419-D-028
Figure 28. ADR391 Line Transient Response
VOLTAGE
TIME (10
µ
s/DIV)
C
BYPASS
= 0.1
µ
F
LINE
INTERRUPTION
V
OUT
0.5V/DIV
1V/DIV
00419-D-029
Figure 29. ADR391 Line Transient Response
VOLTA
GE (
1
V/D
I
V)
TIME (200
µ
s/DIV)
C
L
= 0nF
V
LOAD
ON
V
OUT
LOAD OFF
00419-D-030
Figure 30. ADR391 Load Transient Response
VOLTA
GE (
1
V/D
I
V)
TIME (200
µ
s/DIV)
C
L
= 1nF
V
OUT
V
LOAD
ON
LOAD OFF
00419-D-031
Figure 31. ADR391 Load Transient Response
VOLTA
GE (
1
V/D
I
V)
TIME (200
µ
s/DIV)
C
L
= 100nF
V
OUT
V
LOAD
ON
LOAD OFF
00419-D-032
Figure 32. ADR391 Load Transient Response
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 14 of 20
VOLTAGE
TIME (20
µ
s/DIV)
V
OUT
V
IN
V
IN
= 15V
5V/DIV
2V/DIV
00419-D-033
Figure 33. ADR391 Turn-On Response Time at 15 V
VOLTAGE
TIME (40
µ
s/DIV)
V
OUT
V
IN
V
IN
= 15V
5V/DIV
2V/DIV
00419-D-034
Figure 34. ADR391 Turn-Off Response at 15 V
VOLTA
G
E
TIME (200
µ
s/DIV)
C
BYPASS
= 0.1
µ
F
V
IN
V
OUT
5V/DIV
2V/DIV
00419-D-035
Figure 35. ADR391 Turn-On/Turn-Off Response at 5 V
VOLTAGE
TIME (200
µ
s/DIV)
R
L
= 500
V
OUT
V
IN
5V/DIV
2V/DIV
00419-D-036
Figure 36. ADR391 Turn-On/Turn-Off Response at 5 V
VOLTA
GE (
5
V/D
I
V)
TIME (200
µ
s/DIV)
R
L
= 500
C
L
= 100nF
V
OUT
V
IN
5V/DIV
2V/DIV
00419-D-037
Figure 37. ADR391 Turn-On/Turn-Off Response at 5 V
FREQUENCY (Hz)
10
1M
100
RIP
P
L
E
RE
J
E
CTION (dB)
1k
10k
100k
80
60
120
40
20
0
20
40
60
80
100
00419-D-038
Figure 38. Ripple Rejection vs. Frequency
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 15 of 20
FREQUENCY (Hz)
10
1M
100
OUTP
UT IMP
E
D
ANCE
(
)
1k
10k
100k
100
90
0
80
70
60
50
40
30
20
10
C
L
= 0
µ
F
C
L
= 0.1
µ
F
C
L
= 1
µ
F
00419-D-039
Figure 39. Output Impedance vs. Frequency
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 16 of 20
THEORY OF OPERATION
Band gap references are the high performance solution for low
supply voltage and low power voltage reference applications,
and the ADR390/ADR391/ADR392/ADR395 are no exception.
The uniqueness of these devices lies in the architecture. As
shown in Figure 40, the ideal zero TC band gap voltage is
referenced to the output, not to ground. Therefore, if noise
exists on the ground line, it is greatly attenuated on V
OUT
. The
band gap cell consists of the PNP pair, Q51 and Q52, running at
unequal current densities. The difference in V
BE
results in a
voltage with a positive TC, which is amplified by a ratio of
R54
R58
2 ×
This PTAT voltage, combined with V
BE
s of Q51 and Q52,
produces a stable band gap voltage.
Reduction in the band gap curvature is performed by the ratio
of the resistors R44 and R59, one of which is linearly
temperature dependent. Precision laser trimming and other
patented circuit techniques are used to further enhance the
drift performance.
SHDN
R60
Q51
R54
R61
R53
Q52
R58
R59
R44
R48
R49
Q1
V
IN
V
OUT (FORCE)
V
OUT (SENSE)
GND
00419-D-040
Figure 40. Simplified Schematic
DEVICE POWER DISSIPATION CONSIDERATIONS
The ADR390/ADR391/ADR392/ADR395 are capable of deli-
vering load currents to 5 mA, with an input voltage that ranges
from 2.8 V (ADR391 only) to 15 V. When these devices are
used in applications with large input voltages, care should be
taken to avoid exceeding the specified maximum power
dissipation or junction temperature because it could result in
premature device failure. The following formula should be used
to calcu-late a device's maximum junction temperature or
dissipation:
JA
A
J
D
T
T
P
=
In this equation, T
J
and T
A
are, respectively, the junction and
ambient temperatures. P
D
is the device power dissipation, and
JA
is the device package thermal resistance.
SHUTDOWN MODE OPERATION
The ADR390/ADR391/ADR392/ADR395 include a shutdown
feature that is TTL/CMOS level compatible. A logic low or a
zero volt condition on the SHDN pin is required to turn the
devices off. During shutdown, the output of the reference
becomes a high impedance state, where its potential would then
be determined by external circuitry. If the shutdown feature is
not used, the SHDN pin should be connected to V
IN
(Pin 2).
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 17 of 20
APPLICATIONS
BASIC VOLTAGE REFERENCE CONNECTION
The circuit shown in Figure 41 illustrates the basic configuration
for the ADR39x family. Decoupling capacitors are not required
for circuit stability. The ADR39x family is capable of driving
capacitive loads from 0 µF to 10 µF. However, a 0.1 µF ceramic
output capacitor is recommended to absorb and deliver the
charge, as required by a dynamic load.
SHUTDOWN
INPUT
C
B
0.1
µ
F
C
B
0.1
µ
F
*
*
OUTPUT
*NOT REQUIRED
ADR39x
SHDN
V
IN
V
OUT(S)
GND
V
OUT(F)
00419-D-041
Figure 41. Basic Configuration for the ADR39x Family
Stacking Reference ICs for Arbitrary Outputs
Some applications may require two reference voltage sources,
which are a combined sum of standard outputs. Figure 42 shows
how this stacked output reference can be implemented.
V
OUT(F)
V
OUT(S)
GND
V
IN
V
OUT2
V
OUT1
U2
1
2
3
4
5
U1
C2
0.1
µ
F
V
IN
3
4
1
2
C2
0.1
µ
F
V
OUT(F)
V
OUT(S)
GND
V
IN
5
OUTPUT TABLE
U1/U2
ADR390/ADR390
ADR391/ADR391
ADR392/ADR392
ADR395/ADR395
V
OUT1
(V)
2.048
2.5
4.096
5
V
OUT2
(V)
4.096
5.0
8.192
10
00419-D-042
SHDN
SHDN
Figure 42. Stacking Voltage References with the
ADR390/ADR391/ADR392/ADR395
Two reference ICs are used, fed from an unregulated input, V
IN
.
The outputs of the individual ICs are simply connected in
series, which provides two output voltages, V
OUT1
and V
OUT2
.
V
OUT1
is the terminal voltage of U1, while V
OUT2
is the sum of
this voltage and the terminal voltage of U2. U1 and U2 are
simply chosen for the two voltages that supply the required
outputs (see the Output Table in Figure 42). For example, if
both U1 and U2 are ADR391s, V
OUT1
is 2.5 V and V
OUT2
is 5.0 V.
While this concept is simple, a precaution is required. Since the
lower reference circuit must sink a small bias current from U2
plus the base current from the series PNP output transistor in
U2, either the external load of U1 or R1 must provide a path for
this current. If the U1 minimum load is not well defined, the R1
resistor should be used and set to a value that will conservatively
pass 600 µA of current with the applicable V
OUT1
across it. Note
that the two U1 and U2 reference circuits are treated locally as
macrocells; each has its own bypasses at input and output for
best stability. Both U1 and U2 in this circuit can source dc
currents up to their full rating. The minimum input voltage,
V
IN
, is determined by the sum of the outputs, V
OUT2
, plus the
dropout voltage of U2.
A Negative Precision Reference without Precision
Resistors
A negative reference can be easily generated by adding an A1 op
amp and is configured as shown in Figure 43. V
OUTF
and V
OUTS
are at virtual ground and, therefore, the negative reference can
be taken directly from the output of the op amp. The op amp
must be dual-supply, low offset, and rail-to-rail if the negative
supply voltage is close to the reference output.
+V
DD
V
DD
V
REF
V
OUT(S)
V
OUT(F)
V
IN
GND
A1
2
4
3
5
1
00419-D-043
SHDN
Figure 43. Negative Reference
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 18 of 20
General-Purpose Current Source
Many times in low power applications, the need arises for a
precision current source that can operate on low supply vol-
tages. ADR390/ADR391/ADR392/ADR395 can be configured
as a precision current source. As shown in Figure 45, the circuit
configuration is a floating current source with a grounded load.
The reference's output voltage is bootstrapped across R
SET
,
which sets the output current into the load. With this
configuration, circuit precision is maintained for load currents
in the range from the reference's supply current, typically 90 µA
to approximately 5 mA.
V
IN
ADR39x
GND
V
OUT
I
OUT
= I
SET
+ I
SY
(I
SET
)
R1
I
SY
ADJUST
R
SET
P1
R
L
V
OUT
V
IN
R1
0.1
µ
F
I
SY
(I
SET
)
I
SET
00419-D-044
SHDN
Figure 44. A General-Purpose Current Source
High Power Performance with Current Limit
In some cases, the user may want higher output current
delivered to a load and still achieve better than 0.5% accuracy
out of the ADR39x. The accuracy for a reference is normally
specified on the data sheet with no load. However, the output
voltage changes with load current.
The circuit shown in Figure 45 provides high current without
compromising the accuracy of the ADR39x. The series pass
transistor Q1 provides up to 1 A load current. The ADR39x
delivers only the base drive to Q1 through the force pin. The
sense pin of the ADR39x is a regulated output and is connected
to the load.
The transistor Q2 protects Q1 during short-circuit limit faults
by robbing its base drive. The maximum current is
I
LMAX
0.6 V/R
S
I
L
V
IN
R1
4.7k
Q2
Q2N2222
Q2N4921
Q1
R
S
R
L
SHDN
V
IN
V
OUT (SENSE)
V
OUT (FORCE)
GND
U1
ADR39x
00419-D-045
Figure 45. ADR39x for High Power Performance with Current Limit
A similar circuit function can also be achieved with the
Darlington transistor configuration, as shown in Figure 46.
ADR39x
V
IN
R1
4.7k
Q2
Q2N2222
Q2N4921
R
S
R
L
V
IN
V
OUT (SENSE)
V
OUT (FORCE)
GND
Q1
U1
00419-D-046
SHDN
Figure 46. ADR39x for High Output Current
with Darlington Drive Configuration
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 19 of 20
OUTLINE DIMENSIONS
PIN 1
1.60 BSC
2.80 BSC
1.90
BSC
0.95 BSC
1
3
4
5
2
0.20
0.08
0.60
0.45
0.30
8°
4°
0.50
0.30
0.10 MAX
SEATING
PLANE
1.00 MAX
0.90
0.87
0.84
COMPLIANT TO JEDEC STANDARDS MO-193AB
2.90 BSC
Figure 47. 5-Lead Thin Small Outline Transistor Package [TSOT]
(UJ-5)
Dimensions shown in millimeters
ORDERING GUIDE
Models
Output
Voltage
(V
O
)
Initial
Accuracy
(mV) (%)
Temperature
Coefficient
(ppm/°C)
Package
Description
Package
Option Branding
Number
of Parts
per Reel
Temperature
Range
ADR390AUJZ-REEL7
1
2.048
6
0.29
25
TSOT
UJ-5
R0A
3,000
40°C to +125°C
ADR390AUJZ-R2
1
2.048
6
0.29
25
TSOT
UJ-5
R0A
250
40°C to +125°C
ADR390BUJZ-REEL7
1
2.048
4
0.19
9
TSOT
UJ-5
R0B
3,000
40°C to +125°C
ADR390BUJZ-R2
1
2.048
4
0.19
9
TSOT
UJ-5
R0B
250
40°C to +125°C
ADR391AUJZ-REEL7
1
2.5
6
0.24
25
TSOT
UJ-5
R1A
3,000
40°C to +125°C
ADR391AUJZ-R2
1
2.5
6
0.24
25
TSOT
UJ-5
R1A
250
40°C to +125°C
ADR391BUJZ-REEL7
1
2.5
4
0.16
9
TSOT
UJ-5
R1B
3,000
40°C to +125°C
ADR391BUJZ-R2
1
2.5
4
0.16
9
TSOT
UJ-5
R1B
250
40°C to +125°C
ADR392AUJZ-REEL7
1
4.096
6
0.15
25
TSOT
UJ-5
RCA
3,000
40°C to +125°C
ADR392AUJZ-R2
1
4.096
6
0.15
25
TSOT
UJ-5
RCA
250
40°C to +125°C
ADR392BUJZ-REEL7
1
4.096
5
0.12
9
TSOT
UJ-5
RCB
3,000
40°C to +125°C
ADR392BUJZ-R2
1
4.096
5
0.12
9
TSOT
UJ-5
RCB
250
40°C to +125°C
ADR395AUJZ-REEL7
1
5.0
6
0.12
25
TSOT
UJ-5
RDA
3,000
40°C to +125°C
ADR395AUJZ-R2
1
5.0
6
0.12
25
TSOT
UJ-5
RDA
250
40°C to +125°C
ADR395BUJZ-REEL7
1
5.0
5
0.10
9
TSOT
UJ-5
RDB
3,000
40°C to +125°C
ADR395BUJZ-R2
1
5.0
5
0.10
9
TSOT
UJ-5
RDB
250
40°C to +125°C
1
Z = Pb-free part.
ADR390/ADR391/ADR392/ADR395
Rev. F | Page 20 of 20
NOTES
© 2005 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
C0041905/05(F)
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