Ultralow Noise, LDO XFET Voltage
References with Current Sink and Source
ADR440/ADR441/ADR443/ADR444/ADR445
PIN CONFIGURATIONS
Ultralow noise (0.1 Hz to 10 Hz)
ADR440: 1 μV p-p
ADR441: 1.2 μV p-p
ADR443: 1.4 μV p-p
ADR444: 1.8 μV p-p
ADR445: 2.25 μV p-p
Superb temperature coefficient
A grade: 10 ppm/°C
B grade: 3 ppm/°C
Low dropout operation: 500 mV
Input range: (VOUT + 500 mV) to 18 V
High output source and sink current
+10 mA and −5 mA, respectively
Wide temperature range: −40°C to +125°C
TP 1
VIN 2
NC 3
GND 4
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
TOP VIEW
(Not to Scale)
8
TP
7
NC
6
VOUT
5
TRIM
NOTES
1. NC = NO CONNECT
2. TP = TEST PIN (DO NOT CONNECT)
05428-001
FEATURES
TP 1
VIN 2
NC 3
GND 4
APPLICATIONS
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
TOP VIEW
(Not to Scale)
8
TP
7
NC
6
VOUT
5
TRIM
NOTES
1. NC = NO CONNECT
2. TP = TEST PIN (DO NOT CONNECT)
Precision data acquisition systems
High resolution data converters
Battery-powered instrumentation
Portable medical instruments
Industrial process control systems
Precision instruments
Optical control circuits
05428-002
Figure 1. 8-Lead SOIC_N (R-Suffix)
Figure 2. 8-Lead MSOP (RM-Suffix)
GENERAL DESCRIPTION
The ADR44x series is a family of XFET® voltage references
featuring ultralow noise, high accuracy, and low temperature
drift performance. Using Analog Devices, Inc., patented
temperature drift curvature correction and XFET (eXtra
implanted junction FET) technology, voltage change vs.
temperature nonlinearity in the ADR44x is greatly minimized.
The XFET references offer better noise performance than
buried Zener references, and XFET references operate off
low supply voltage headroom (0.5 V). This combination of
features makes the ADR44x family ideally suited for precision
signal conversion applications in high-end data acquisition
systems, optical networks, and medical applications.
The ADR44x family has the capability to source up to 10 mA of
output current and sink up to −5 mA. It also comes with a trim
terminal to adjust the output voltage over a 0.5% range without
compromising performance.
Offered in two electrical grades, the ADR44x family is available in 8-lead MSOP and narrow SOIC packages. All versions
are specified over the extended industrial temperature range of
−40°C to +125°C.
Table 1. Selection Guide
Model
ADR440A
ADR440B
ADR441A
ADR441B
ADR443A
ADR443B
ADR444A
ADR444B
ADR445A
ADR445B
Output
Voltage
(V)
2.048
2.048
2.500
2.500
3.000
3.000
4.096
4.096
5.000
5.000
Initial
Accuracy
(mV)
±3
±1
±3
±1
±4
±1.2
±5
±1.6
±6
±2
Temperature
Coefficient
(ppm/°C)
10
3
10
3
10
3
10
3
10
3
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
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.
Trademarks and registered trademarks 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 ©2005–2010 Analog Devices, Inc. All rights reserved.
ADR440/ADR441/ADR443/ADR444/ADR445
TABLE OF CONTENTS
Features .............................................................................................. 1 Theory of Operation ...................................................................... 14 Applications....................................................................................... 1 Power Dissipation Considerations........................................... 14 Pin Configurations ........................................................................... 1 Basic Voltage Reference Connections ..................................... 14 General Description ......................................................................... 1 Noise Performance ..................................................................... 14 Revision History ............................................................................... 2 Turn-On Time ............................................................................ 14 Specifications..................................................................................... 3 Applications Information .............................................................. 15 ADR440 Electrical Characteristics............................................. 3 Output Adjustment .................................................................... 15 ADR441 Electrical Characteristics............................................. 4 Bipolar Outputs .......................................................................... 15 ADR443 Electrical Characteristics............................................. 5 Programmable Voltage Source ................................................. 15 ADR444 Electrical Characteristics............................................. 6 Programmable Current Source ................................................ 16 ADR445 Electrical Characteristics............................................. 7 High Voltage Floating Current Source .................................... 16 Absolute Maximum Ratings............................................................ 8 Precision Output Regulator (Boosted Reference)................. 16 Thermal Resistance ...................................................................... 8 Outline Dimensions ....................................................................... 17 ESD Caution.................................................................................. 8 Ordering Guide .......................................................................... 18 Typical Performance Characteristics ............................................. 9 REVISION HISTORY
11/10—Rev. D to Rev. E
Deleted Negative Reference Section............................................. 15
Deleted Figure 37; Renumbered Sequentially ............................ 15
3/10—Rev. C to Rev. D
Changes to Figure 37...................................................................... 15
Updated Outline Dimensions ....................................................... 18
3/08—Rev. B to Rev. C
Changes to Table 8............................................................................ 8
Change to Figure 11 ....................................................................... 10
Changes to Figure 36...................................................................... 15
Changes to Figure 39...................................................................... 16
Changes to Figure 41...................................................................... 17
Updated Outline Dimensions ....................................................... 18
9/06—Rev. 0 to Rev. A
Updated Format..................................................................Universal
Changes to Features ..........................................................................1
Changes to Pin Configurations .......................................................1
Changes to Specifications Section...................................................3
Changes to Figure 4 and Figure 5....................................................9
Inserted Figure 6 and Figure 7.........................................................9
Changes to Figure 15...................................................................... 11
Changes to Power Dissipation Considerations Section ............ 14
Changes to Figure 35 and Figure 36............................................. 15
Changes to Figure 38 and Table 9................................................. 16
Updated Outline Dimensions....................................................... 18
Changes to Ordering Guide .......................................................... 19
10/05—Revision 0: Initial Version
8/07—Rev. A to Rev. B
Change to Table 2, Ripple Rejection Ratio Specification ............ 3
Change to Table 3, Ripple Rejection Ratio Specification ............ 4
Change to Table 4, Ripple Rejection Ratio Specification ............ 5
Change to Table 5, Ripple Rejection Ratio Specification ............ 6
Change to Table 6, Ripple Rejection Ratio Specification ............ 7
Rev. E | Page 2 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
SPECIFICATIONS
ADR440 ELECTRICAL CHARACTERISTICS
VIN = 3 V to 18 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted.
Table 2.
Parameter
OUTPUT VOLTAGE
A Grade
B Grade
INITIAL ACCURACY
A Grade
Symbol
VO
Conditions
Min
Typ
Max
Unit
2.045
2.047
2.048
2.048
2.051
2.049
V
V
3
0.15
1
0.05
mV
%
mV
%
10
3
+20
ppm/°C
ppm/°C
ppm/V
+50
ppm/mA
+50
3.75
ppm/mA
mA
μV p-p
nV/√Hz
μs
ppm
ppm
dB
mA
V
mV
VOERR
B Grade
TEMPERATURE DRIFT
A Grade
B Grade
LINE REGULATION
LOAD REGULATION
TCVO
ΔVO/ΔVIN
ΔVO/ΔILOAD
ΔVO/ΔILOAD
QUIESCENT CURRENT
VOLTAGE NOISE
VOLTAGE NOISE DENSITY
TURN-ON SETTLING TIME
LONG-TERM STABILITY 1
OUTPUT VOLTAGE HYSTERESIS
RIPPLE REJECTION RATIO
SHORT CIRCUIT TO GND
SUPPLY VOLTAGE OPERATING RANGE
SUPPLY VOLTAGE HEADROOM
1
IIN
eN p-p
eN
tR
VO
VO_HYS
RRR
ISC
VIN
VIN − VO
−40°C < TA < +125°C
−40°C < TA < +125°C
−40°C < TA < +125°C
ILOAD = 0 mA to 10 mA, VIN = 3.5 V,
−40°C < TA < +125°C
ILOAD = 0 mA to −5 mA, VIN = 3.5 V,
−40°C < TA < +125°C
No load, −40°C < TA < +125°C
0.1 Hz to 10 Hz
1 kHz
−20
2
1
+10
−50
−50
3
1
45
10
50
70
−80
27
1000 hours
fIN = 1 kHz
3
500
18
The long-term stability specification is noncumulative. The drift in the subsequent 1000-hour period is significantly lower than in the first 1000-hour period.
Rev. E | Page 3 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
ADR441 ELECTRICAL CHARACTERISTICS
VIN = 3 V to 18 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted.
Table 3.
Parameter
OUTPUT VOLTAGE
A Grade
B Grade
INITIAL ACCURACY
A Grade
Symbol
VO
Conditions
Min
Typ
Max
Unit
2.497
2.499
2.500
2.500
2.503
2.501
V
V
3
0.12
1
0.04
mV
%
mV
%
10
3
20
ppm/°C
ppm/°C
ppm/V
+50
ppm/mA
+50
3.75
ppm/mA
mA
μV p-p
nV/√Hz
μs
ppm
ppm
dB
mA
V
mV
VOERR
B Grade
TEMPERATURE DRIFT
A Grade
B Grade
LINE REGULATION
LOAD REGULATION
TCVO
ΔVO/ΔVIN
ΔVO/ΔILOAD
ΔVO/ΔILOAD
QUIESCENT CURRENT
VOLTAGE NOISE
VOLTAGE NOISE DENSITY
TURN-ON SETTLING TIME
LONG-TERM STABILITY 1
OUTPUT VOLTAGE HYSTERESIS
RIPPLE REJECTION RATIO
SHORT CIRCUIT TO GND
SUPPLY VOLTAGE OPERATING RANGE
SUPPLY VOLTAGE HEADROOM
1
IIN
eN p-p
eN
tR
VO
VO_HYS
RRR
ISC
VIN
VIN − VO
−40°C < TA < +125°C
−40°C < TA < +125°C
−40°C < TA < +125°C
ILOAD = 0 mA to 10 mA, VIN = 4 V,
−40°C < TA < +125°C
ILOAD = 0 mA to −5 mA, VIN = 4 V,
−40°C < TA < +125°C
No load, −40°C < TA < +125°C
0.1 Hz to 10 Hz
1 kHz
2
1
10
−50
−50
3
1.2
48
10
50
70
−80
27
1000 hours
fIN = 1 kHz
3
500
18
The long-term stability specification is noncumulative. The drift in subsequent 1000-hour period is significantly lower than in the first 1000-hour period.
Rev. E | Page 4 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
ADR443 ELECTRICAL CHARACTERISTICS
VIN = 3.5 V to 18 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted.
Table 4.
Parameter
OUTPUT VOLTAGE
A Grade
B Grade
INITIAL ACCURACY
A Grade
Symbol
VO
Conditions
Min
Typ
Max
Unit
2.996
2.9988
3.000
3.000
3.004
3.0012
V
V
4
0.13
1.2
0.04
mV
%
mV
%
10
3
20
ppm/°C
ppm/°C
ppm/V
+50
ppm/mA
+50
3.75
ppm/mA
mA
μV p-p
nV/√Hz
μs
ppm
ppm
dB
mA
V
mV
VOERR
B Grade
TEMPERATURE DRIFT
A Grade
B Grade
LINE REGULATION
LOAD REGULATION
TCVO
ΔVO/ΔVIN
ΔVO/ΔILOAD
ΔVO/ΔILOAD
QUIESCENT CURRENT
VOLTAGE NOISE
VOLTAGE NOISE DENSITY
TURN-ON SETTLING TIME
LONG-TERM STABILITY 1
OUTPUT VOLTAGE HYSTERESIS
RIPPLE REJECTION RATIO
SHORT CIRCUIT TO GND
SUPPLY VOLTAGE OPERATING RANGE
SUPPLY VOLTAGE HEADROOM
1
IIN
eN p-p
eN
tR
VO
VO_HYS
RRR
ISC
VIN
VIN − VO
−40°C < TA < +125°C
−40°C < TA < +125°C
−40°C < TA < +125°C
ILOAD = 0 mA to 10 mA, VIN = 5 V,
−40°C < TA < +125°C
ILOAD = 0 mA to −5 mA, VIN = 5 V,
−40°C < TA < +125°C
No load, −40°C < TA < +125°C
0.1 Hz to 10 Hz
1 kHz
2
1
10
−50
−50
3
1.4
57.6
10
50
70
−80
27
1000 hours
fIN = 1 kHz
3.5
500
18
The long-term stability specification is noncumulative. The drift in the subsequent 1000-hour period is significantly lower than in the first 1000-hour period.
Rev. E | Page 5 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
ADR444 ELECTRICAL CHARACTERISTICS
VIN = 4.6 V to 18 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted.
Table 5.
Parameter
OUTPUT VOLTAGE
A Grade
B Grade
INITIAL ACCURACY
A Grade
Symbol
VO
Conditions
Min
Typ
Max
Unit
4.091
4.0944
4.096
4.096
4.101
4.0976
V
V
5
0.13
1.6
0.04
mV
%
mV
%
10
3
20
ppm/°C
ppm/°C
ppm/V
+50
ppm/mA
+50
3.75
ppm/mA
mA
μV p-p
nV/√Hz
μs
ppm
ppm
dB
mA
V
mV
VOERR
B Grade
TEMPERATURE DRIFT
A Grade
B Grade
LINE REGULATION
LOAD REGULATION
TCVO
ΔVO/ΔVIN
ΔVO/ΔILOAD
ΔVO/ΔILOAD
QUIESCENT CURRENT
VOLTAGE NOISE
VOLTAGE NOISE DENSITY
TURN-ON SETTLING TIME
LONG-TERM STABILITY 1
OUTPUT VOLTAGE HYSTERESIS
RIPPLE REJECTION RATIO
SHORT CIRCUIT TO GND
SUPPLY VOLTAGE OPERATING RANGE
SUPPLY VOLTAGE HEADROOM
1
IIN
eN p-p
eN
tR
VO
VO_HYS
RRR
ISC
VIN
VIN − VO
−40°C < TA < +125°C
−40°C < TA < +125°C
−40°C < TA < +125°C
ILOAD = 0 mA to 10 mA, VIN = 5.5 V,
−40°C < TA < +125°C
ILOAD = 0 mA to −5 mA, VIN = 5.5 V,
−40°C < TA < +125°C
No load, −40°C < TA < +125°C
0.1 Hz to 10 Hz
1 kHz
2
1
10
−50
−50
3
1.8
78.6
10
50
70
−80
27
1000 hours
fIN = 1 kHz
4.6
500
18
The long-term stability specification is noncumulative. The drift in the subsequent 1000-hour period is significantly lower than in the first 1000-hour period.
Rev. E | Page 6 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
ADR445 ELECTRICAL CHARACTERISTICS
VIN = 5.5 V to 18 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted.
Table 6.
Parameter
OUTPUT VOLTAGE
A Grade
B Grade
INITIAL ACCURACY
A Grade
Symbol
VO
Conditions
Min
Typ
Max
Unit
4.994
4.998
5.000
5.000
5.006
5.002
V
V
6
0.12
2
0.04
mV
%
mV
%
10
3
20
ppm/°C
ppm/°C
ppm/V
+50
ppm/mA
+50
3.75
ppm/mA
mA
μV p-p
nV/√Hz
μs
ppm
ppm
dB
mA
V
mV
VOERR
B Grade
TEMPERATURE DRIFT
A Grade
B Grade
LINE REGULATION
LOAD REGULATION
TCVO
ΔVO/ΔVIN
ΔVO/ΔILOAD
ΔVO/ΔILOAD
QUIESCENT CURRENT
VOLTAGE NOISE
VOLTAGE NOISE DENSITY
TURN-ON SETTLING TIME
LONG-TERM STABILITY 1
OUTPUT VOLTAGE HYSTERESIS
RIPPLE REJECTION RATIO
SHORT CIRCUIT TO GND
SUPPLY VOLTAGE OPERATING RANGE
SUPPLY VOLTAGE HEADROOM
1
IIN
eN p-p
eN
tR
VO
VO_HYS
RRR
ISC
VIN
VIN − VO
−40°C < TA < +125°C
−40°C < TA < +125°C
−40°C < TA < +125°C
ILOAD = 0 mA to 10 mA, VIN = 6.5 V,
−40°C < TA < +125°C
ILOAD = 0 mA to −5 mA, VIN = 6.5 V,
−40°C < TA < +125°C
No load, −40°C < TA < +125°C
0.1 Hz to 10 Hz
1 kHz
2
1
10
−50
−50
3
2.25
90
10
50
70
–80
27
1000 hours
fIN = 1 kHz
5.5
500
18
The long-term stability specification is noncumulative. The drift in the subsequent 1000-hour period is significantly lower than in the first 1000-hour period.
Rev. E | Page 7 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
THERMAL RESISTANCE
Table 7.
θJA is specified for the worst-case conditions, that is, 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
20 V
Indefinite
−65°C to +125°C
−40°C to +125°C
−65°C to +150°C
300°C
Table 8. Thermal Resistance
Package Type
8-Lead SOIC (R-Suffix)
8-Lead MSOP (RM-Suffix)
ESD CAUTION
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; 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.
Rev. E | Page 8 of 20
θJA
130
132.5
θJC
43
43.9
Unit
°C/W
°C/W
ADR440/ADR441/ADR443/ADR444/ADR445
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 7 V, TA = 25°C, CIN = COUT = 0.1 μF, unless otherwise noted.
4.0980
2.051
4.0975
2.050
OUTPUT VOLTAGE (V)
OUTPUT VOLTAGE (V)
4.0970
2.049
2.048
2.047
DEVICE 1
4.0965
DEVICE 2
4.0960
DEVICE 3
4.0955
4.0950
2.046
–20
0
20
40
60
80
100
4.0940
–40
120
05428-005
05428-042
2.045
–40
4.0945
–25
–10
5
TEMPERATURE (°C)
80
95
110
125
Figure 6. ADR444 Output Voltage vs. Temperature
2.5020
5.006
2.5015
5.004
OUTPUT VOLTAGE (V)
2.5010
2.5005
2.5000
5.002
5.000
4.998
4.996
2.4990
–40
05428-003
2.4995
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
4.994
–40
125
05428-043
OUTPUT VOLTAGE (V)
Figure 3. ADR440 Output Voltage vs. Temperature
20
35
50
65
TEMPERATURE (°C)
–20
0
20
40
60
80
100
120
TEMPERATURE (°C)
Figure 7. ADR445 Output Voltage vs. Temperature
Figure 4. ADR441 Output Voltage vs. Temperature
4.0
3.0020
3.0005
DEVICE 2
3.0000
DEVICE 3
2.9995
2.9990
2.9985
2.9980
–40
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
3.5
+125°C
+25°C
3.0
–40°C
2.5
05428-006
DEVICE 1
05428-004
OUTPUT VOLTAGE (V)
3.0010
SUPPLY CURRENT (mA)
3.0015
2.0
4
125
6
8
10
12
INPUT VOLTAGE (V)
14
16
Figure 8. ADR441 Supply Current vs. Input Voltage
Figure 5. ADR443 Output Voltage vs. Temperature
Rev. E | Page 9 of 20
18
ADR440/ADR441/ADR443/ADR444/ADR445
10
LINE REGULATION (ppm/V)
SUPPLY CURRENT (mA)
4.0
3.5
3.0
2.5
8
6
4
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
0
–40
125
Figure 9. ADR441 Supply Current vs. Temperature
05428-010
2.0
–40
05428-007
2
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
125
Figure 12. ADR441 Line Regulation vs. Temperature
3.5
60
ILOAD = 0mA TO 10mA
3.4
LOAD REGULATION (ppm/mA)
3.2
3.1
+125°C
3.0
2.9
+25°C
2.8
2.7
–40°C
05428-008
7.3
9.3
11.3
13.3
15.3
INPUT VOLTAGE (V)
VIN = 18V
50
45
VIN = 6V
40
35
2.6
2.5
5.3
55
17.3
30
–40
19.3
Figure 10. ADR445 Supply Current vs. Input Voltage
05428-011
SUPPLY CURRENT (mA)
3.3
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
125
Figure 13. ADR441 Load Regulation vs. Temperature
3.25
7
6
LINE REGULATION (ppm/V)
3.05
2.95
5
4
3
2
2.85
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
125
Figure 11. ADR445 Supply Current vs. Temperature
1
0
–40
05428-012
2.75
–40
05428-009
SUPPLY CURRENT (mA)
3.15
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
Figure 14. ADR445 Line Regulation vs. Temperature
Rev. E | Page 10 of 20
125
ADR440/ADR441/ADR443/ADR444/ADR445
50
1.0
VIN = 6V
0.9
40
DIFFERENTIAL VOLTAGE (V)
30
20
10
0
–10
–20
ILOAD = 0mA TO –5mA
0.8
+125°C
0.7
0.6
0.5
+25°C
0.4
–40°C
0.3
–40
–50
–40
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
05428-016
0.2
–30
05428-013
LOAD REGULATION (ppm/mA)
ILOAD = 0mA TO +10mA
0.1
0
–5
125
Figure 15. ADR445 Load Regulation vs. Temperature
0
5
LOAD CURRENT (mA)
10
Figure 18. ADR445 Minimum Input/Output
Differential Voltage vs. Load Current
0.7
0.5
NO LOAD
0.4
MINIMUM HEADROOM (V)
DIFFERENTIAL VOLTAGE (V)
0.6
0.5
+125°C
0.4
+25°C
–40°C
0.3
0.2
0.3
0.2
05428-014
0
–10
–5
0
LOAD CURRENT (mA)
5
10
Figure 16. ADR441 Minimum Input/Output
Differential Voltage vs. Load Current
0
–40
05428-017
0.1
0.1
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
125
Figure 19. ADR445 Minimum Headroom vs. Temperature
0.5
CIN = COUT = 0.1µF
NO LOAD
VIN = 5V/DIV
0.3
0.2
0.1
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
TIME = 10µs/DIV
125
Figure 17. ADR441 Minimum Headroom vs. Temperature
Figure 20. ADR441 Turn-On Response
Rev. E | Page 11 of 20
05428-018
0
–40
VOUT = 1V/DIV
05428-015
MINIMUM HEADROOM (V)
0.4
ADR440/ADR441/ADR443/ADR444/ADR445
CIN = COUT = 0.1µF
CIN = 0.1µF
COUT = 10µF
LOAD OFF
LOAD ON
VIN = 5V/DIV
5mV/DIV
TIME = 200µs/DIV
05428-023
05428-019
VOUT = 1V/DIV
TIME = 200µs/DIV
Figure 21. ADR441 Turn-Off Response
Figure 24. ADR441 Load Transient Response
CIN = COUT = 0.1µF
CIN = 0.1µF
COUT = 10µF
LOAD OFF
LOAD ON
VIN = 5V/DIV
5mV/DIV
05428-022
TIME = 200µs/DIV
05428-020
VOUT = 1V/DIV
TIME = 200µs/DIV
Figure 25. ADR441 Load Transient Response
Figure 22. ADR441 Turn-On Response
CIN = 0.1µF
COUT = 10µF
2V/DIV
4V
1µV/DIV
CH 1 p-p
1.18µV
TIME = 1s/DIV
Figure 26. ADR441 0.1 Hz to 10.0 Hz Voltage Noise
Figure 23. ADR441 Line Transient Response
Rev. E | Page 12 of 20
05428-024
TIME = 100µs/DIV
05428-021
2mV/DIV
ADR440/ADR441/ADR443/ADR444/ADR445
16
14
NUMBER OF PARTS
12
50µV/DIV
CH 1 p-p
49µV
10
8
6
150
130
90
70
50
30
10
–10
–30
–50
–70
–90
–110
–130
0
110
05428-028
2
–150
TIME = 1s/DIV
05428-025
4
DEVIATION (ppm)
Figure 30. ADR441 Typical Output Voltage Hysteresis
Figure 27. ADR441 10 Hz to 10 kHz Voltage Noise
10
9
OUTPUT IMPEDANCE (Ω)
8
1µV/DIV
CH 1 p-p
2.24µV
7
ADR445
6
5
ADR443
4
3
ADR441
05428-026
TIME = 1s/DIV
1
0
10
100
1k
FREQUENCY (Hz)
10k
05428-029
2
100k
Figure 31. Output Impedance vs. Frequency
Figure 28. ADR445 0.1 Hz to 10.0 Hz Voltage Noise
0
50µV/DIV
TIME = 1s/DIV
05428-027
CH 1 p-p
66µV
–20
–30
–40
–50
–60
–70
–80
05428-030
RIPPLE REJECTION RATIO (dB)
–10
–90
–100
100
1k
10k
FREQUENCY (Hz)
100k
Figure 32. Ripple Rejection Ratio vs. Frequency
Figure 29. ADR445 10 Hz to 10 kHz Voltage Noise
Rev. E | Page 13 of 20
1M
ADR440/ADR441/ADR443/ADR444/ADR445
THEORY OF OPERATION
The intrinsic reference voltage is around 0.5 V with a negative
temperature coefficient of about –120 ppm/°C. This slope is
essentially constant to the dielectric constant of silicon, and it can
be closely compensated for by adding a correction term generated
in the same fashion as the proportional-to-absolute temperature
(PTAT) term used to compensate band gap references. The
advantage of an XFET reference is its correction term, which is
approximately 20 times lower and requires less correction than
that of a band gap reference. Because most of the noise of a band
gap reference comes from the temperature compensation
circuitry, the XFET results in much lower noise.
POWER DISSIPATION CONSIDERATIONS
The ADR44x family of references is guaranteed to deliver load
currents to 10 mA with an input voltage that ranges from 3 V to
18 V. When these devices are used in applications at higher
currents, use the following equation to account for the
temperature effects of increases in power dissipation:
TJ = PD × θJA + TA
where:
TJ and TA are the junction and ambient temperatures,
respectively.
PD is the device power dissipation.
θJA is the device package thermal resistance.
BASIC VOLTAGE REFERENCE CONNECTIONS
The ADR44x family requires a 0.1 μF capacitor on the input
and the output for stability. Although not required for operation,
a 10 μF capacitor at the input can help with line voltage
transient performance.
TP 1
VIN
Figure 33 shows the basic topology of the ADR44x series. The
temperature correction term is provided by a current source with
a value designed to be proportional to the absolute temperature.
The general equation is
VOUT = G (ΔVP − R1 × IPTAT)
ADR44x devices are created by on-chip adjustment of R2
and R3 to achieve the different voltage options at the
reference output.
VIN
I1
I1
ADR44x
VOUT
R2
*
∆VP
R1
*EXTRA CHANNEL IMPLANT
VOUT = G (∆VP – R1 × IPTAT)
R3
GND
05428-033
IPTAT
2
+
10µF
0.1µF
NC 3
GND
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
8
TP
7
NC
6
VOUT
TOP VIEW
4
5 TRIM
(Not to Scale)
NOTES
1. NC = NO CONNECT
2. TP = TEST PIN (DO NOT CONNECT)
(1)
where:
G is the gain of the reciprocal of the divider ratio.
ΔVP is the difference in pinch-off voltage between the two JFETs.
IPTAT is the positive temperature coefficient correction current.
(2)
0.1µF
05428-034
The ADR44x series of references uses a new reference generation
technique known as XFET (eXtra implanted junction FET).
This technique yields a reference with low dropout, good
thermal hysteresis, and exceptionally low noise. The core of the
XFET reference consists of two junction field-effect transistors
(JFETs), one of which has an extra channel implant to raise its
pinch-off voltage. By running the two JFETs at the same drain
current, the difference in pinch-off voltage can be amplified
and used to form a highly stable voltage reference.
Figure 34. Basic Voltage Reference Configuration
NOISE PERFORMANCE
The noise generated by the ADR44x family of references is
typically less than 1.4 μV p-p over the 0.1 Hz to 10.0 Hz band
for ADR440, ADR441, and ADR443. Figure 26 shows the 0.1 Hz
to 10 Hz noise of the ADR441, which is only 1.2 μV p-p. The
noise measurement is made with a band-pass filter composed of
a 2­pole high-pass filter with a corner frequency at 0.1 Hz and a
2­pole low-pass filter with a corner frequency at 10.0 Hz.
TURN-ON TIME
Upon application of power (cold start), the time required for
the output voltage to reach its final value within a specified
error band is defined as the turn-on settling time. Two components normally associated with this are the time for the active
circuits to settle and the time for the thermal gradients on the
chip to stabilize. Figure 20 and Figure 21 show the turn-on and
turn-off settling times for the ADR441.
Figure 33. Simplified Schematic Device
Rev. E | Page 14 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
APPLICATIONS INFORMATION
+VDD
OUTPUT ADJUSTMENT
The ADR44x family features a TRIM pin that allows the user to
adjust the output voltage of the part over a limited range. This
allows errors from the reference and overall system errors to be
trimmed out by connecting a potentiometer between the output
and the ground, with the wiper connected to the TRIM pin.
Figure 35 shows the optimal trim configuration. R1 allows fine
adjustment of the output and is not always required. RP should
be sufficiently large so that the maximum output current from
the ADR44x is not exceeded.
2
VIN
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
0.1µF
+5V
VOUT 6
GND
0.1µF
R1
R2
10kΩ 10kΩ
4
+10V
R3
5kΩ
2
–10V
VIN
VOUT 6
4
0.1µF
R1
100kΩ
PROGRAMMABLE VOLTAGE SOURCE
RP
10kΩ
R2
1kΩ
Figure 35. ADR44x Trim Function
Using the trim function has a negligible effect on the temperature
performance of the ADR44x. However, all resistors need to be
low temperature coefficient resistors, or errors may occur.
To obtain different voltages than those offered by the ADR44x,
some extra components are needed. In Figure 37, two potentiometers are used to set the desired voltage and the buffering
amplifier provides current drive. The potentiometer connected
between VOUT and GND, with its wiper connected to the
noninverting input of the operational amplifier, takes care of
coarse trim. The second potentiometer, with its wiper connected
to the trim terminal of the ADR44x, is used for fine adjustment.
Resolution depends on the end-to-end resistance value and the
resolution of the selected potentiometer.
BIPOLAR OUTPUTS
+VDD
By connecting the output of the ADR44x to the inverting terminal of an operational amplifier, it is possible to obtain both
positive and negative reference voltages. Care must be taken
when choosing Resistors R1 and R2 (see Figure 36). These
resistors must be matched as closely as possible to ensure minimal differences between the negative and positive outputs. In
addition, care must be taken to ensure performance over
temperature. Use low temperature coefficient resistors if the
circuit is used over temperature; otherwise, differences exist
between the two outputs.
2
VIN
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
ADJ VREF
VOUT 6
GND
4
R1
R2
10kΩ 10kΩ
05428-038
TRIM 5
GND
Figure 36. ADR44x Bipolar Outputs
VO = ±0.5%
05428-035
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
05428-036
–5V
0.1µF
Figure 37. Programmable Voltage Source
For a completely programmable solution, replace the two
potentiometers in Figure 37 with one Analog Devices dual
digital potentiometer, offered with either an SPI or an I2C
interface. These interfaces set the position of the wiper on both
potentiometers and allow the output voltage to be set. Table 9
lists compatible Analog Devices digital potentiometers.
Rev. E | Page 15 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
Table 9. Digital Potentiometer Parts
Part No.
AD5251
AD5207
AD5242
AD5262
AD5282
AD5252
AD5232
AD5235
ADN2850
1
No. of
Channels
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
2.00
No. of
Positions
64.00
256.00
256.00
256.00
256.00
256.00
256.00
1024.00
1024.00
ITF
I2C
SPI
I2C
SPI
I2C
I2C
SPI
SPI
SPI
HIGH VOLTAGE FLOATING CURRENT SOURCE
VDD1
(V)
5.5
5.5
5.5
15
15
5.5
5.5
5.5
5.5
R (kΩ)
1, 10, 50, 100
10, 50, 100
10, 100, 1M
20, 50, 200
20, 50, 100
1, 10, 50, 100
10, 50, 100
25, 250
25, 250
Use the circuit in Figure 39 to generate a floating current source
with minimal self heating. This particular configuration can
operate on high supply voltages, determined by the breakdown
voltage of the N-channel JFET.
+VS
SST111
VISHAY
2
VIN
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
Can also use a negative supply.
VOUT 6
GND
–VS
Figure 39. Floating Current Source
It is possible to build a programmable current source using a
setup similar to the programmable voltage source, as shown in
Figure 38. The constant voltage on the gate of the transistor sets
the current through the load. Varying the voltage on the gate
changes the current. This circuit does not require a dual digital
potentiometer.
PRECISION OUTPUT REGULATOR
(BOOSTED REFERENCE)
VIN
2
VIN
VCC
CIN
0.1µF
2
VIN
GND
15V
VO
RL
200Ω
COUT
0.1µF
CL
1µF
–V
05428-041
4
VOUT 6
4
2N7002
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
VOUT 6
RSENSE
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
GND
05428-040
4
PROGRAMMABLE CURRENT SOURCE
Figure 40. Boosted Output Reference
0.1µF
AD5259
ILOAD
05428-039
0.1µF
2N3904
OP90
Adding a negative supply to the operational amplifier allows
the user to produce a negative programmable reference
by connecting the reference output to the inverting terminal
of the operational amplifier. Choose feedback resistors to
minimize errors over temperature.
Figure 38. Programmable Current Source
Higher current drive capability can be obtained without
sacrificing accuracy by using the circuit in Figure 40. The
operational amplifier regulates the MOSFET turn-on, forcing
VO to equal the VREF. Current is then drawn from VIN, allowing
increased current drive capability. The circuit allows a 50 mA
load; if higher current drive is required, use a larger MOSFET.
For fast transient response, add a buffer at VO to aid with
capacitive loading.
Rev. E | Page 16 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
OUTLINE DIMENSIONS
5.00 (0.1968)
4.80 (0.1890)
8
4.00 (0.1574)
3.80 (0.1497)
5
1
4
1.27 (0.0500)
BSC
0.25 (0.0098)
0.10 (0.0040)
6.20 (0.2441)
5.80 (0.2284)
1.75 (0.0688)
1.35 (0.0532)
0.51 (0.0201)
0.31 (0.0122)
COPLANARITY
0.10
SEATING
PLANE
0.50 (0.0196)
0.25 (0.0099)
45°
8°
0°
0.25 (0.0098)
0.17 (0.0067)
1.27 (0.0500)
0.40 (0.0157)
012407-A
COMPLIANT TO JEDEC STANDARDS MS-012-AA
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 41. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-8)
Dimensions shown in millimeters and (inches)
3.20
3.00
2.80
8
3.20
3.00
2.80
1
5.15
4.90
4.65
5
4
PIN 1
IDENTIFIER
0.65 BSC
0.95
0.85
0.75
15° MAX
1.10 MAX
0.40
0.25
6°
0°
0.23
0.09
COMPLIANT TO JEDEC STANDARDS MO-187-AA
Figure 42. 8-Lead Mini Small Outline Package [MSOP]
(RM-8)
Dimensions show in millimeters
Rev. E | Page 17 of 20
0.80
0.55
0.40
10-07-2009-B
0.15
0.05
COPLANARITY
0.10
ADR440/ADR441/ADR443/ADR444/ADR445
ORDERING GUIDE
Model 1
ADR440ARZ
ADR440ARZ-REEL7
ADR440ARMZ
ADR440ARMZ-REEL7
ADR440BRZ
ADR440BRZ-REEL7
ADR441ARZ
ADR441ARZ-REEL7
ADR441ARMZ
ADR441ARMZ-REEL7
ADR441BRZ
ADR441BRZ-REEL7
ADR443ARZ
ADR443ARZ-REEL7
ADR443ARMZ
ADR443ARMZ-REEL7
ADR443BRZ
ADR443BRZ-REEL7
ADR444ARZ
ADR444ARZ-REEL7
ADR444ARMZ
ADR444ARMZ-REEL7
ADR444BRZ
ADR444BRZ-REEL7
ADR445ARZ
ADR445ARZ-REEL7
ADR445ARMZ
ADR445ARMZ-REEL7
ADR445BRZ
ADR445BRZ-REEL7
1
Output
Voltage (V)
2.048
2.048
2.048
2.048
2.048
2.048
2.500
2.500
2.500
2.500
2.500
2.500
3.000
3.000
3.000
3.000
3.000
3.000
4.096
4.096
4.096
4.096
4.096
4.096
5.000
5.000
5.000
5.000
5.000
5.000
Initial
Accuracy
±mV %
3
0.15
3
0.15
3
0.15
3
0.15
1
0.05
1
0.05
3
0.12
3
0.12
3
0.12
3
0.12
1
0.04
1
0.04
4
0.13
4
0.13
4
0.13
4
0.13
1.2
0.04
1.2
0.04
5
0.13
5
0.13
5
0.13
5
0.13
1.6
0.04
1.6
0.04
6
0.12
6
0.12
6
0.12
6
0.12
2
0.04
2
0.04
Temperature
Coefficient
Package (ppm/°C)
10
10
10
10
3
3
10
10
10
10
3
3
10
10
10
10
3
3
10
10
10
10
3
3
10
10
10
10
3
3
Z = RoHS Compliant Part.
Rev. E | Page 18 of 20
Package
Description
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead MSOP
8-Lead MSOP
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead MSOP
8-Lead MSOP
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead MSOP
8-Lead MSOP
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead MSOP
8-Lead MSOP
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead SOIC_N
8-Lead MSOP
8-Lead MSOP
8-Lead SOIC_N
8-Lead SOIC_N
Branding
R01
R01
R02
R02
R03
R03
R04
R04
R05
R05
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
–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
–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
–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
Package
Option
R-8
R-8
RM-8
RM-8
R-8
R-8
R-8
R-8
RM-8
RM-8
R-8
R-8
R-8
R-8
RM-8
RM-8
R-8
R-8
R-8
R-8
RM-8
RM-8
R-8
R-8
R-8
R-8
RM-8
RM-8
R-8
R-8
ADR440/ADR441/ADR443/ADR444/ADR445
NOTES
Rev. E | Page 19 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
NOTES
I2C refers to a communications protocol originally developed by Philips Semiconductors (now NXP Semiconductors).
©2005–2010 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05428-0-11/10(E)
Rev. E | Page 20 of 20