FEATURES
PIN CONFIGURATION
Compact 5-lead TSOT package
Low temperature coefficient
B grade: 9 ppm/°C
A grade: 25 ppm/°C
Initial accuracy
B grade: ±4 mV maximum (ADR391)
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
140 μA maximum in operation
No external capacitor required
Output current: 5 mA
Automotive grade available
Wide temperature range: −40°C to +125°C
SHDN 1
VIN 2
ADR391/
ADR392/
ADR395
5 GND
VOUT (SENSE) 3 (Not to Scale) 4 VOUT (FORCE)
00419-001
Data Sheet
Micropower, Low Noise Precision Voltage
References with Shutdown
ADR391/ADR392/ADR395
Figure 1. 5-Lead TSOT (UJ Suffix)
Table 1.
Model
ADR391B
ADR391A
ADR392B
ADR392A
ADR395B
ADR395A
Output
Voltage (VO)
2.5
2.5
4.096
4.096
5.0
5.0
Temperature
Coefficient (ppm/°C)
9
25
9
25
9
25
Accuracy
(mV)
±4
±6
±5
±6
±5
±6
APPLICATIONS
Battery-powered instrumentation
Portable medical instrumentation
Data acquisition systems
Industrial process controls
Automotive
GENERAL DESCRIPTION
The ADR391/ADR392/ADR395 are precision 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 patented
temperature drift curvature correction techniques from Analog
Devices, Inc., the ADR39x references achieve a low 9 ppm/°C of
temperature drift in the TSOT package.
Rev. I
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.
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ADR391/ADR392/ADR395
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
ESD Caution...................................................................................6
Applications ....................................................................................... 1
Typical Performance Characteristics ..............................................7
Pin Configuration ............................................................................. 1
Terminology .................................................................................... 13
General Description ......................................................................... 1
Theory of Operation ...................................................................... 14
Revision History ............................................................................... 2
Device Power Dissipation Considerations .............................. 14
Specifications..................................................................................... 3
Shutdown Mode Operation ...................................................... 14
ADR391 Electrical Characteristics............................................. 3
Applications Information .............................................................. 15
ADR392 Electrical Characteristics............................................. 4
Basic Voltage Reference Connection ....................................... 15
ADR395 Electrical Characteristics............................................. 5
Capacitors .................................................................................... 17
Absolute Maximum Ratings............................................................ 6
Outline Dimensions ....................................................................... 18
Thermal Resistance ...................................................................... 6
Ordering Guide .......................................................................... 18
REVISION HISTORY
4/2019—Rev. H to Rev. I
Change to General Description Section ........................................ 1
Added Figure 19; Renumbered Sequentially ................................ 9
Changes to Shutdown Mode Operation Section ........................ 14
Added Figure 35 and Figure 36..................................................... 14
Deleted Figure 40; Renumbered Sequentially ............................ 17
Changes to Ordering Guide .......................................................... 18
Updated Outline Dimensions ....................................................... 18
10/2009—Rev. G to Rev. H
Deleted ADR390 ................................................................. Universal
Changes to Ordering Guide Section ............................................ 18
2/2008—Rev. F to Rev. G
Changes to Ripple Rejection Ration Parameter (Table 2) ........... 3
Changes to Ripple Rejection Ration Parameter (Table 3) ........... 4
Changes to Ripple Rejection Ration Parameter (Table 4) ........... 5
Changes to Ripple Rejection Ration Parameter (Table 5) ........... 6
Changes to Figure 7 .......................................................................... 9
Changes to Outline Dimensions................................................... 19
Changes to Ordering Guide .......................................................... 19
5/2005—Rev. E to Rev. F
Changes to Table 5 ............................................................................ 7
Changes to Figure 2 .......................................................................... 9
4/2004—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
4/2004—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
10/2002—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
5/2002—Rev. A to Rev. B
Edits to Layout .................................................................... Universal
Changes to Figure 6 ........................................................................ 13
Rev. I | Page 2 of 20
Data Sheet
ADR391/ADR392/ADR395
SPECIFICATIONS
ADR391 ELECTRICAL CHARACTERISTICS
VIN = 2.8 V to 15 V, TA = 25°C, unless otherwise noted.
Table 2.
Parameter
OUTPUT VOLTAGE
Symbol
VO
INITIAL ACCURACY
VOERR
TEMPERATURE COEFFICIENT
TCVO
SUPPLY VOLTAGE HEADROOM
LINE REGULATION
LOAD REGULATION
VIN − VO
ΔVO/ΔVIN
ΔVO/ΔILOAD
QUIESCENT CURRENT
IIN
VOLTAGE NOISE
TURN-ON SETTLING TIME
LONG-TERM STABILITY1
OUTPUT VOLTAGE HYSTERESIS
RIPPLE REJECTION RATIO
SHORT CIRCUIT TO GND
en p-p
tR
ΔVO
ΔVO_HYS
RRR
ISC
SHUTDOWN PIN
Shutdown Supply Current
Shutdown Logic Input Current
Shutdown Logic Low
Shutdown Logic High
ISHDN
ILOGIC
VINL
VINH
1
Conditions
A grade
B grade
A grade
A grade
B grade
B grade
A grade, −40°C < TA < +125°C
B grade, −40°C < TA < +125°C
Min
2.494
2.496
Typ
2.5
2.5
Max
2.506
2.504
6
0.24
4
0.16
25
9
10
25
60
140
120
140
300
VIN = 2.8 V to 15 V, −40°C < TA < +125°C
ILOAD = 0 mA to 5 mA, −40°C < TA < +85°C, VIN = 3 V
ILOAD = 0 mA to 5 mA, −40°C < TA < +125°C, VIN = 3 V
No load
−40°C < TA < +125°C
0.1 Hz to 10 Hz
5
20
50
100
−80
25
30
1000 hours
fIN = 60 Hz
VIN = 5 V
VIN = 15 V
3
500
0.8
2.4
The long-term stability specification is noncumulative. The drift of subsequent 1000 hour periods is significantly lower than in the first 1000 hour period.
Rev. I | Page 3 of 20
Unit
V
V
mV
%
mV
%
ppm/°C
ppm/°C
mV
ppm/V
ppm/mA
ppm/mA
μA
μA
μV p-p
μs
ppm
ppm
dB
mA
mA
μA
nA
V
V
ADR391/ADR392/ADR395
Data Sheet
ADR392 ELECTRICAL CHARACTERISTICS
VIN = 4.3 V to 15 V, TA = 25°C, unless otherwise noted.
Table 3.
Parameter
OUTPUT VOLTAGE
Symbol
VO
INITIAL ACCURACY
VOERR
TEMPERATURE COEFFICIENT
TCVO
SUPPLY VOLTAGE HEADROOM
LINE REGULATION
LOAD REGULATION
QUIESCENT CURRENT
VIN − VO
ΔVO/ΔVIN
ΔVO/ΔILOAD
IIN
VOLTAGE NOISE
TURN-ON SETTLING TIME
LONG-TERM STABILITY1
OUTPUT VOLTAGE HYSTERESIS
RIPPLE REJECTION RATIO
SHORT CIRCUIT TO GND
en p-p
tR
ΔVO
ΔVO_HYS
RRR
ISC
SHUTDOWN PIN
Shutdown Supply Current
Shutdown Logic Input Current
Shutdown Logic Low
Shutdown Logic High
ISHDN
ILOGIC
VINL
VINH
1
Conditions
A grade
B grade
A grade
A grade
B grade
B grade
A grade, −40°C < TA < +125°C
B grade, −40°C < TA < +125°C
Min
4.090
4.091
Typ
4.096
4.096
Max
4.102
4.101
6
0.15
5
0.12
25
9
10
25
140
120
140
300
VIN = 4.3 V to 15 V, −40°C < TA < +125°C
ILOAD = 0 mA to 5 mA, −40°C < TA < +125°C, VIN = 5 V
No load
−40°C < TA < +125°C
0.1 Hz to 10 Hz
7
20
50
100
−80
25
30
1000 hours
fIN = 60 Hz
VIN = 5 V
VIN = 15 V
3
500
0.8
2.4
The long-term stability specification is noncumulative. The drift of subsequent 1000 hour periods is significantly lower than in the first 1000 hour period.
Rev. I | Page 4 of 20
Unit
V
V
mV
%
mV
%
ppm/°C
ppm/°C
mV
ppm/V
ppm/mA
μA
μA
μV p-p
μs
ppm
ppm
dB
mA
mA
μA
nA
V
V
Data Sheet
ADR391/ADR392/ADR395
ADR395 ELECTRICAL CHARACTERISTICS
VIN = 5.3 V to 15 V, TA = 25°C, unless otherwise noted.
Table 4.
Parameter
OUTPUT VOLTAGE
Symbol
VO
INITIAL ACCURACY
VOERR
TEMPERATURE COEFFICIENT
TCVO
SUPPLY VOLTAGE HEADROOM
LINE REGULATION
LOAD REGULATION
QUIESCENT CURRENT
VIN − VO
ΔVO/ΔVIN
ΔVO/ΔILOAD
IIN
VOLTAGE NOISE
TURN-ON SETTLING TIME
LONG-TERM STABILITY1
OUTPUT VOLTAGE HYSTERESIS
RIPPLE REJECTION RATIO
SHORT CIRCUIT TO GND
en p-p
tR
ΔVO
ΔVO_HYS
RRR
ISC
SHUTDOWN PIN
Shutdown Supply Current
Shutdown Logic Input Current
Shutdown Logic Low
Shutdown Logic High
ISHDN
ILOGIC
VINL
VINH
1
Conditions
A grade
B grade
A grade
A grade
B grade
B grade
A grade, −40°C < TA < +125°C
B grade, −40°C < TA < +125°C
Min
4.994
4.995
Typ
5.000
5.000
Max
5.006
5.005
6
0.12
5
0.10
25
9
10
25
140
120
140
300
VIN = 4.3 V to 15 V, −40°C < TA < +125°C
ILOAD = 0 mA to 5 mA, −40°C < TA < +125°C, VIN = 6 V
No load
−40°C < TA < +125°C
0.1 Hz to 10 Hz
8
20
50
100
−80
25
30
1000 hours
fIN = 60 Hz
VIN = 5 V
VIN = 15 V
3
500
0.8
2.4
The long-term stability specification is noncumulative. The drift of subsequent 1000 hour periods is significantly lower than in the first 1000 hour period.
Rev. I | Page 5 of 20
Unit
V
V
mV
%
mV
%
ppm/°C
ppm/°C
mV
ppm/V
ppm/mA
μA
μA
μV p-p
μs
ppm
ppm
dB
mA
mA
μA
nA
V
V
ADR391/ADR392/ADR395
Data Sheet
ABSOLUTE MAXIMUM RATINGS
At 25°C, unless otherwise noted.
THERMAL RESISTANCE
Table 5.
θJA is specified for the worst-case conditions, that is, for a device
soldered in a circuit board for surface-mount packages.
Parameter
Supply Voltage
Output Short-Circuit Duration to GND
Storage Temperature Range
Operating Temperature Range
Junction Temperature Range
Lead Temperature (Soldering, 60 sec)
Rating
18 V
See derating curves
−65°C to +125°C
−40°C to +125°C
−65°C to +125°C
300°C
Table 6.
Package Type
TSOT (UJ-5)
ESD CAUTION
Stresses at or above those listed under Absolute Maximum
Ratings may cause permanent damage to the product. This is a
stress rating only; functional operation of the product at these
or any other conditions above those indicated in the operational
section of this specification is not implied. Operation beyond
the maximum operating conditions for extended periods may
affect product reliability.
Rev. I | Page 6 of 20
θJA
230
θJC
146
Unit
°C/W
Data Sheet
ADR391/ADR392/ADR395
TYPICAL PERFORMANCE CHARACTERISTICS
2.506
140
SAMPLE 2
2.504
120
SUPPLY CURRENT (µA)
SAMPLE 1
SAMPLE 3
2.500
2.498
+85°C
+25°C
80
–40°C
60
2.496
–5
30
65
TEMPERATURE (°C)
100
125
40
2.5
00419-004
2.494
–40
+125°C
100
Figure 2. ADR391 Output Voltage (VOUT) vs. Temperature
00419-008
VOUT (V)
2.502
5.0
7.5
10.0
INPUT VOLTAGE (V)
12.5
15.0
Figure 5. ADR391 Supply Current vs. Input Voltage
4.100
140
4.098
+125 °C
120
4.094
SAMPLE 2
SAMPLE 1
4.092
100
+25°C
–40°C
80
60
4.090
0
40
TEMPERATURE (°C)
80
125
40
00419-005
4.088
–40
00419-009
VOUT (V)
4.096
SUPPLY CURRENT (µA)
SAMPLE 3
5
Figure 3. ADR392 Output Voltage (VOUT) vs. Temperature
7
9
11
INPUT VOLTAGE (V)
140
5.004
SAMPLE 3
+125°C
120
SUPPLY CURRENT (µA)
5.002
SAMPLE 2
5.000
SAMPLE 1
4.998
4.996
+25°C
100
–40°C
80
–5
30
65
TEMPERATURE (°C)
100
125
Figure 4. ADR395 Output Voltage (VOUT) vs. Temperature
40
5.5
00419-010
60
00419-006
VOUT (V)
15
Figure 6. ADR392 Supply Current vs. Input Voltage
5.006
4.994
–40
13
7.0
8.5
11.5
10.0
INPUT VOLTAGE (V)
13.0
Figure 7. ADR395 Supply Current vs. Input Voltage
Rev. I | Page 7 of 20
14.5
ADR391/ADR392/ADR395
Data Sheet
25
180
20
LINE REGULATION (ppm/V)
160
VIN = 5V
VIN = 3V
140
120
100
15
10
80
–40
–10
20
50
TEMPERATURE (°C)
80
110
125
0
–40
00419-016
5
00419-012
LOAD REGULATION (ppm/mA)
IL = 0mA TO 5mA
–10
20
50
TEMPERATURE (°C)
80
110
125
Figure 11. ADR391 Line Regulation vs. Temperature
Figure 8. ADR391 Load Regulation vs. Temperature
14
90
IL = 0mA TO 5mA
LINE REGULATION (ppm/V)
LOAD REGULATION (ppm/mA)
12
80
70
VIN = 7.5V
60
VIN = 5V
10
8
VIN = 4.4V TO 15V
6
4
50
–5
100
30
65
TEMPERATURE (°C)
125
0
–40
00419-013
40
–40
–5
30
65
TEMPERATURE (°C)
100
125
00419-017
2
Figure 12. ADR392 Line Regulation vs. Temperature
Figure 9. ADR392 Load Regulation vs. Temperature
14
80
IL = 0mA TO 5mA
60
LINE REGULATION (ppm/V)
VIN = 7.5V
VIN = 5V
50
10
VIN = 5.3V TO 15V
8
6
4
40
30
–40
–5
30
65
TEMPERATURE (°C)
100
125
0
–40
–5
30
65
TEMPERATURE (°C)
100
Figure 13. ADR395 Line Regulation vs. Temperature
Figure 10. ADR395 Load Regulation vs. Temperature
Rev. I | Page 8 of 20
125
00419-018
2
00419-014
LOAD REGULATION (ppm/mA)
12
70
Data Sheet
ADR391/ADR392/ADR395
70
3.6
+125°C
60
+85°C
50
TEMPERATURE: +25°C
–40°C
+125°C
+25°C
3.2
FREQUENCY
VIN MIN (V)
3.4
+25°C
3.0
–40°C
40
30
20
2.8
1
2
3
LOAD CURRENT (mA)
4
5
0
–0.56
Figure 14. ADR391 Minimum Input Voltage (VIN) vs. Load Current
VOLTAGE NOISE DENSITY (nV/√Hz)
VIN MIN (V)
1k
900
800
700
+125°C
+25°C
4.4
–40°C
4.2
0
1
2
3
LOAD CURRENT (mA)
4
5
0.19
0.34
VIN = 5V
600
500
400
ADR391
300
200
00419-021
4.0
3.8
–0.26
–0.11
0.04
VOUT DEVIATION (mV)
Figure 17. ADR391 VOUT Hysteresis Distribution
4.8
4.6
–0.41
100
10
Figure 15. ADR392 Minimum Input Voltage (VIN) vs. Load Current
100
1k
FREQUENCY (Hz)
00419-025
0
00419-020
2.6
00419-024
10
10k
Figure 18. Voltage Noise Density vs. Frequency
150
6.0
100
5.8
+125 °C
DRIFT (ppm)
50
+25°C
5.4
–40 °C
5.2
0
–50
5.0
–150
4.6
0
1
2
3
LOAD CURRENT (mA)
4
5
Figure 16. ADR395 Minimum Input Voltage (VIN) vs. Load Current
00419-002
–100
4.8
00419-022
VIN MIN (V)
5.6
0
100
200
300
400 500
600
TIME (Hours)
700
800
900
1000
Figure 19. ADR391 Typical Long-Term Drift Over 1000 Hours
Rev. I | Page 9 of 20
ADR391/ADR392/ADR395
Data Sheet
0
0
VOLTAGE (2µV/DIV)
VOLTAGE (100µV/DIV)
0
0
0
0
0
00419-027
0
00419-026
0
TIME (1s/DIV)
TIME (10µs/DIV)
Figure 23. ADR391 Voltage Noise 10 Hz to 10 kHz
Figure 20. ADR391 Typical Voltage Noise 0.1 Hz to 10 Hz
CL = 0nF
VOUT
LINE
INTERRUPTION
VOLTAGE (1V/DIV)
CBYPASS = 0µF
VOLTAGE
0.5V/DIV
VOUT
VLOAD ON
LOAD OFF
00419-028
00419-030
1V/DIV
TIME (200µs/DIV)
TIME (10µs/DIV)
Figure 24. ADR391 Load Transient Response
Figure 21. ADR391 Line Transient Response
CL = 1nF
VOUT
VOLTAGE (1V/DIV)
CBYPASS = 0.1µF
0.5V/DIV
VOLTAGE
LINE
INTERRUPTION
VOUT
LOAD OFF
VLOAD ON
00419-029
00419-031
1V/DIV
TIME (200µs/DIV)
TIME (10µs/DIV)
Figure 25. ADR391 Load Transient Response
Figure 22. ADR391 Line Transient Response
Rev. I | Page 10 of 20
Data Sheet
ADR391/ADR392/ADR395
CL = 100nF
CBYPASS = 0.1µF
VOUT
VOLTAGE
LOAD OFF
VLOAD ON
5V/DIV
00419-035
VIN
00419-032
VOLTAGE (1V/DIV)
2V/DIV
VOUT
TIME (200µs/DIV)
TIME (200µs/DIV)
Figure 26. ADR391 Load Transient Response
Figure 29. ADR391 Turn-On/Turn-Off Response at 5 V with Capacitance
VIN = 15V
RL = 500Ω
5V/DIV
2V/DIV
VIN
VOLTAGE
2V/DIV
VOUT
5V/DIV
VIN
00419-033
00419-036
VOLTAGE
VOUT
TIME (20µs/DIV)
TIME (200µs/DIV)
Figure 27. ADR391 Turn-On Response Time at 15 V
Figure 30. ADR391 Turn-On/Turn-Off Response at 5 V with Resistor Load
RL = 500Ω
CL = 100nF
VIN = 15V
VIN
5V/DIV
VOLTAGE
2V/DIV
2V/DIV
VIN
5V/DIV
00419-037
VOUT
00419-034
VOLTAGE
VOUT
TIME (200µs/DIV)
TIME (40µs/DIV)
Figure 28. ADR391 Turn-Off Response at 15 V
Figure 31. ADR391 Turn-On/Turn-Off Response at 5 V
Rev. I | Page 11 of 20
Data Sheet
100
60
90
40
80
20
0
–20
–40
–60
60
CL = 0µF
50
40
30
20
–80
–100
–120
10
70
100
1k
10k
FREQUENCY (Hz)
100k
CL = 1µF
10
0
10
1M
100
1k
10k
FREQUENCY (Hz)
CL = 0.1µF
100k
Figure 33. Output Impedance vs. Frequency
Figure 32. Ripple Rejection vs. Frequency
Rev. I | Page 12 of 20
1M
00419-039
OUTPUT IMPEDANCE (Ω)
80
00419-038
RIPPLE REJECTION (dB)
ADR391/ADR392/ADR395
Data Sheet
ADR391/ADR392/ADR395
TERMINOLOGY
Temperature Coefficient
The change of output voltage with respect to operating temperature
changes normalized by the output voltage at 25°C. This parameter
is expressed in ppm/°C and can be determined by
TCVO ppm/C
VO T2 – VO T1
VO 25C T2 – T1
10 6
Long-Term Stability
Typical shift of output voltage at 25°C on a sample of parts
subjected to a test of 1000 hours at 25°C.
ΔVO = VO(t0) − VO(t1)
V (t ) VO (t1 )
VO [ppm] O 0
106
VO (t 0 )
(1)
where:
VO (25°C) is VO at 25°C.
VO (T1) is VO at Temperature 1.
VO (T2) is VO at Temperature 2.
(2)
where:
VO (t0) is VO at 25°C at Time 0.
VO (t1) is VO at 25°C after 1000 hours operation at 25°C.
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-permillion 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 milliampere,
parts-per-million per milliampere, or ohms of dc output resistance.
Thermally Induced Output Voltage Hysteresis
The change of output voltage after the device cycles through
the 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.
VO_HYS = VO(25°C) − VO_TC
VO _ HYS [ppm]
VO (25 C ) VO _ TC
VO (25 C )
(3)
10 6
where:
VO (25°C) is VO at 25°C.
VO_TC is VO at 25°C after a temperature cycle from +25°C to
−40°C to +125°C and back to +25°C.
Rev. I | Page 13 of 20
(4)
ADR391/ADR392/ADR395
Data Sheet
THEORY OF OPERATION
Band gap references are the high performance solution for low
supply voltage and low power voltage reference applications,
and the ADR391/ADR392/ADR395 are no exception. The
uniqueness of these devices lies in the architecture. As shown in
Figure 34, 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 VOUT. The band gap cell
consists of the PNP pair, Q51 and Q52, running at unequal
current densities. The difference in VBE results in a voltage with
a positive TC, which is amplified by a ratio of
2
R58
R54
This PTAT voltage, combined with VBEs of Q51 and Q52,
produces a stable band gap voltage.
Reduction in the band gap curvature is performed by the ratio
of 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.
VIN
the maximum junction temperature or dissipation of the device:
PD
VOUT (FORCE)
SHUTDOWN MODE OPERATION
The ADR391/ADR392/ADR395 include a shutdown feature
that is TTL/CMOS level compatible. A logic low or a 0 V
condition on the SHDN pin is required to turn the devices off.
During shutdown mode, the output of the reference becomes a
high impedance state, where its potential is determined by external
circuitry. If the ADR39x is powered on with the SHDN pin held
low during power on, one of the following conditions must be met:
Capacitor placed between VIN and SHDN as shown in
Figure 35, or
Low pass filter the input as shown in Figure 36, or
≥200 ms power supply ramp rate to VIN.
VOUT (SENSE)
R59
(5)
JA
where:
TJ and TA are, respectively, the junction and ambient temperatures.
PD is the device power dissipation.
θJA is the device package thermal resistance.
Q1
TJ – TA
SHUTDOWN
R44
INPUT
R58
CB
GND
SHDN
0.1µF
*
ADR39x
VIN
0.1µF
VOUT (FORCE)
VOUT (SENSE)
R49
R54
Q51
R53
*NOT REQUIRED
Q52
*
CB
OUTPUT
00419-134
SHDN
0.1µF
R61
GND
SHUTDOWN
SHDN
Figure 34. Simplified Schematic
INPUT
10µF CB
DEVICE POWER DISSIPATION CONSIDERATIONS
The ADR391/ADR392/ADR395 are capable of delivering 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 calculate
GND
ADR39x
10kΩ
*NOT REQUIRED
*
0.1µF
VIN
VOUT (FORCE)
VOUT (SENSE)
CB
*
OUTPUT
0.1µF
Figure 36. Low Pass Filter at VIN Pin
If the shutdown feature is not used, the SHDN pin must be
connected to VIN (Pin 2).
Rev. I | Page 14 of 20
00419-135
R60
00419-040
Figure 35. VIN and SHDN Capacitor
R48
Data Sheet
ADR391/ADR392/ADR395
APPLICATIONS INFORMATION
BASIC VOLTAGE REFERENCE CONNECTION
The circuit shown in Figure 37 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
GND
SHDN
ADR39x
CB
*
VIN
VOUT (FORCE)
VOUT (SENSE)
0.1µF
CB
*NOT REQUIRED
*
OUTPUT
00419-041
INPUT
0.1µF
Figure 37. 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 38 shows
how this stacked output reference can be implemented.
ADR391/ADR391
ADR392/ADR392
ADR395/ADR395
VOUT1 (V) VOUT2 (V)
2.5
4.096
5
VIN
A negative reference can be easily generated by adding an A1
op amp and is configured as shown in Figure 39. VOUT (FORCE)
and VOUT (SENSE) 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.
5.0
8.192
10
U2
VIN
C2
0.1µF
While this concept is simple, a precaution is required. Because
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 an external resistor must
provide a path for this current. If the U1 minimum load is not
well defined, the external resistor should be used and set to a
value that conservatively passes 600 μA of current with the
applicable VOUT1 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, VIN, is determined by the sum of
the outputs, VOUT2, plus the dropout voltage of U2.
A Negative Precision Reference without Precision Resistors
OUTPUT TABLE
U1/U2
Two reference ICs are used, fed from an unregulated input, VIN.
The outputs of the individual ICs are connected in series, which
provide two output voltages, VOUT1 and VOUT2. VOUT1 is the
terminal voltage of U1, while VOUT2 is the sum of this voltage
and the terminal voltage of U2. U1 and U2 are chosen for the
two voltages that supply the required outputs (see the Output
Table in Figure 38). For example, if both U1 and U2 are ADR391s,
VOUT1 is 2.5 V and VOUT2 is 5.0 V.
SHDN
VOUT (FORCE)
+VDD
VOUT2
VOUT (SENSE)
GND
VIN
VOUT (FORCE)
SHDN
VOUT (SENSE)
U1
GND
VOUT1
VOUT (SENSE)
–VREF
A1
00419-042
GND
–VDD
Figure 38. Stacking Voltage References with the ADR391/ADR392/ADR395
Rev. I | Page 15 of 20
Figure 39. Negative Reference
00419-043
C2
0.1µF
VIN
SHDN
VOUT (FORCE)
ADR391/ADR392/ADR395
Data Sheet
General-Purpose Current Source
High Power Performance with Current Limit
Many times in low power applications, the need arises for a
precision current source that can operate on low supply voltages.
The ADR391/ADR392/ADR395 can be configured as a precision
current source. As shown in Figure 40, the circuit configuration
is a floating current source with a grounded load. The reference
output voltage is bootstrapped across RSET, which sets the output
current into the load. With this configuration, circuit precision
is maintained for load currents in the range from the reference
supply current, typically 90 μA to approximately 5 mA.
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.
VIN
The circuit shown in Figure 41 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
SHDN
VOUT (SENSE)
ADR39x
ILMAX ≈ 0.6 V/RS
VIN
ISET
GND
R1
R1
VIN
R1
4.7kΩ
RSET
ISY
ADJUST
SHDN
GND
VIN
P1
Q1
Q2N4921
VOUT (FORCE)
IOUT = ISET + ISY (ISET )
VOUT (SENSE)
00419-044
RL
U1
Q2
Q2N2222
RS
ADR39x
Figure 40. A General-Purpose Current Source
RL
IL
00419-045
0.1µF
Figure 41. 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 42.
VIN
R1
4.7kΩ
U1
SHDN
GND
VIN
Q1
Q2N2222
VOUT (FORCE)
VOUT (SENSE)
ADR39x
Q2
Q2N4921
RS
RL
Figure 42. ADR39x for High Output Current
with Darlington Drive Configuration
Rev. I | Page 16 of 20
00419-D-046
VOUT (FORCE)
ISY (ISET)
(6)
Data Sheet
ADR391/ADR392/ADR395
CAPACITORS
Output Capacitor
Input 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.
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.
Rev. I | Page 17 of 20
ADR391/ADR392/ADR395
Data Sheet
OUTLINE DIMENSIONS
3.05
2.90
2.75
TOP VIEW
1.75
1.60
1.45
5
1
4
2
3.05
2.80
2.55
3
0.95 BSC
1.90 REF
SIDE VIEW
END VIEW
1.00 MAX
0.10 MAX
SEATING
PLANE
0.50
0.30
PKG-000882
0.20
0.08
8°
4°
0°
0.60
0.45
0.30
COMPLIANT TO JEDEC STANDARDS MO-193-AB
04-05-2017-B
0.90
0.70
Figure 43. 5-Lead Thin Small Outline Transistor Package [TSOT]
(UJ-5)
Dimensions shown in millimeters
ORDERING GUIDE
Model1,2
ADR391AUJZ-REEL7
ADR391AUJZ-R2
ADR391BUJZ-REEL7
ADR392AUJZ-REEL7
ADR392BUJZ-REEL7
ADR392WBUJZ-R7
ADR395AUJZ-REEL7
ADR395BUJZ-REEL7
1
2
Output
Voltage
(VO)
2.5
2.5
2.5
4.096
4.096
4.096
5.0
5.0
Initial
Accuracy
(mV) (%)
±6
0.24
±6
0.24
±4
0.16
±6
0.15
±5
0.12
±5
0.12
±6
0.12
±5
0.10
Temperature
Coefficient
(ppm/°C)
25
25
9
25
9
9
25
9
Package
Description
5-Lead TSOT
5-Lead TSOT
5-Lead TSOT
5-Lead TSOT
5-Lead TSOT
5-Lead TSOT
5-Lead TSOT
5-Lead TSOT
Z = RoHS Compliant Part.
The ADR392WBUJZ-R7 is an automotive grade model.
Rev. I | Page 18 of 20
Package
Option
UJ-5
UJ-5
UJ-5
UJ-5
UJ-5
UJ-5
UJ-5
UJ-5
Marking
Code
R1A
R1A
R1B
RCA
RCB
RCB
RDA
RDB
Ordering
Quantity
3000
250
3000
3000
3000
3000
3000
3000
Temperature
Range
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
Data Sheet
ADR391/ADR392/ADR395
NOTES
Rev. I | Page 19 of 20
ADR391/ADR392/ADR395
Data Sheet
NOTES
©2000–2019 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D00419-0-4/19(I)
Rev. I | Page 20 of 20
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