AD ADR441BRZ Ultralow noise, ldo xfet voltage references with current sink and source Datasheet

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
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
APPLICATIONS
GND 4
Precision data acquisition systems
High resolution data converters
Battery-powered instrumentations
Portable medical instruments
Industrial process control systems
Precision instruments
Optical control circuits
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)
05428-002
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. A
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
©2006 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..................................................................................... 15
ADR440 Electrical Characteristics............................................. 3
Output Adjustment .................................................................... 15
ADR441 Electrical Characteristics............................................. 4
Bipolar Outputs .......................................................................... 15
ADR443 Electrical Characteristics............................................. 5
Negative Reference..................................................................... 15
ADR444 Electrical Characteristics............................................. 6
Programmable Voltage Source ................................................. 16
ADR445 Electrical Characteristics............................................. 7
Programmable Current Source ................................................ 16
Absolute Maximum Ratings............................................................ 8
High Voltage Floating Current Source .................................... 16
Thermal Resistance ...................................................................... 8
Precision Output Regulator (Boosted Reference).................. 17
ESD Caution.................................................................................. 8
Outline Dimensions ....................................................................... 18
Typical Performance Characteristics ............................................. 9
Ordering Guide .......................................................................... 19
REVISION HISTORY
9/06—Rev. 0 to Rev. A
Updated Format..................................................................Universal
Changes to Features.......................................................................... 1
Changes to Pin Configurations....................................................... 1
Changes to the 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 the 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
Rev. A | 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
−75
27
1000 hours
fIN = 10 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. A | 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
−75
27
1000 hours
fIN = 10 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. A | 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
−75
27
1000 hours
fIN = 10 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. A | 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
−75
27
1000 hours
fIN = 10 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. A | 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
–75
27
1000 hours
fIN = 10 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. A | 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_N (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. A | Page 8 of 20
θJA
130
190
θJC
43
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.
2.051
2.5020
2.050
OUTPUT VOLTAGE (V)
2.5010
2.5005
2.5000
2.049
2.048
2.047
2.046
2.4990
–40
05428-003
2.4995
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
2.045
–40
125
–20
0
20
40
60
80
100
120
TEMPERATURE (°C)
Figure 3. ADR441 Output Voltage vs. Temperature
Figure 6. ADR440 Output Voltage vs. Temperature
5.006
3.0020
3.0015
OUTPUT VOLTAGE (V)
5.004
3.0010
OUTPUT VOLTAGE (V)
05428-042
OUTPUT VOLTAGE (V)
2.5015
UNIT 1
3.0005
UNIT 2
3.0000
UNIT 3
2.9995
5.002
5.000
4.998
2.9990
05428-004
2.9980
–40
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
4.994
–40
125
05428-043
4.996
2.9985
–20
0
20
40
60
80
100
120
TEMPERATURE (°C)
Figure 4. ADR443 Output Voltage vs. Temperature
Figure 7. ADR445 Output Voltage vs. Temperature
4.0980
4.0
4.0975
4.0965
4.0960
UNIT 2
UNIT 3
4.0955
4.0950
4.0945
4.0940
–40
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
3.5
+125°C
–40°C
2.5
2.0
125
Figure 5. ADR444 Output Voltage vs. Temperature
+25°C
3.0
05428-006
SUPPLY CURRENT (mA)
UNIT 1
05428-005
OUTPUT VOLTAGE (V)
4.0970
4
6
8
10
12
INPUT VOLTAGE (V)
14
16
Figure 8. ADR441 Supply Current vs. Input Voltage
Rev. A | Page 9 of 20
18
ADR440/ADR441/ADR443/ADR444/ADR445
10
3.5
LINE REGULATION (ppm/V)
SUPPLY CURRENT (mA)
4.0
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
60
3.5
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
ILOAD = 0mA TO 10mA
45
VIN = 6V
40
35
2.6
2.5
5.3
55
17.3
30
–40
19.3
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
Figure 10. ADR445 Supply Current vs. Input Voltage
7
3.25
LINE REGULATIOIN (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
1
0
–40
05428-012
2.75
–40
05428-009
QUIESCENT CURRENT (mA)
6
3.15
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
Figure 14. ADR445 Line Regulation vs. Temperature
Figure 11. ADR445 Quiescent Current vs. Temperature
Rev. A | Page 10 of 20
125
ADR440/ADR441/ADR443/ADR444/ADR445
50
1.0
0.9
20
10
VIN = 6V
0
–10
–20
ILOAD = 0mA TO –5mA
–30
–40
–50
–40
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
0.8
+125°C
0.7
0.6
0.5
+25°C
0.4
–40°C
0.3
0.2
05428-016
30
DIFFERENTIAL VOLTAGE (V)
ILOAD = 0mA TO +10mA
05428-013
LOAD REGULATION (ppm/mA)
40
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)
0.5
+125°C
0.4
+25°C
–40°C
0.3
0.2
0.3
0.2
0.1
05428-014
0.1
0
–10
–5
0
LOAD CURRENT (mA)
5
10
Figure 16. ADR441 Minimum Input/Output
Differential Voltage vs. Load Current
0
–40
05428-017
DIFFERENTIAL VOLTAGE (V)
0.6
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
125
Figure 19. ADR445 Minimum Headroom vs. Temperature
0.5
NO LOAD
CIN, COUT = 0.1µF
VIN = 5V/DIV
0.3
0.2
0.1
–25
–10
5
20
35
50
65
TEMPERATURE (°C)
80
95
110
125
Figure 17. ADR441 Minimum Headroom vs. Temperature
VOUT = 1V/DIV
TIME = 10µs/DIV
Figure 20. ADR441 Turn-On Response
Rev. A | Page 11 of 20
05428-018
0
–40
05428-015
MINIMUM HEADROOM (V)
0.4
ADR440/ADR441/ADR443/ADR444/ADR445
CIN, COUT = 0.1µF
CIN, COUT = 0.1µF
LOAD OFF
LOAD ON
VIN = 5V/DIV
5mV/DIV
TIME = 200µs/DIV
TIME = 200µs/DIV
05428-022
05428-019
VOUT = 1V/DIV
Figure 24. ADR441 Load Transient Response
Figure 21. ADR441 Turn-Off Response
CIN = 0.1µF
COUT = 10µF
CIN = 0.1µF
COUT = 10µF
LOAD OFF
LOAD ON
VIN = 5V/DIV
5mV/DIV
TIME = 200µs/DIV
Figure 22. ADR441 Turn-On Response
05428-023
TIME = 200µs/DIV
05428-020
VOUT = 1V/DIV
Figure 25. ADR441 Load Transient Response
CIN = 0.1µF
COUT = 10µF
2V/DIV
4V
1µV/DIV
CH1 p-p
1.18µV
TIME = 1s/DIV
Figure 23. ADR441 Line Transient Response
Figure 26. ADR441 0.1 Hz to 10.0 Hz Voltage Noise
Rev. A | Page 12 of 20
05428-024
TIME = 100µs/DIV
05428-021
2mV/DIV
ADR440/ADR441/ADR443/ADR444/ADR445
16
14
50µV/DIV
CH1 p-p
49µV
NUMBER OF PARTS
12
10
8
6
4
150
130
90
70
50
30
10
–10
–30
–50
–70
–90
–110
–130
05428-025
–150
0
TIME = 1s/DIV
110
05428-028
2
DEVIATION (PPM)
Figure 30. ADR441 Typical Output Voltage Hysteresis
Figure 27. ADR441 10 Hz to 10 kHz Voltage Noise
10
9
CH1 p-p
2.24µV
7
ADR445
6
5
ADR443
4
3
2
ADR441
1
0
05428-026
TIME = 1s/DIV
10
100
1k
FREQUENCY (Hz)
10k
05428-029
1µV/DIV
OUTPUT IMPEDANCE (Ω)
8
100k
Figure 31. Output Impedance vs. Frequency
Figure 28. ADR445 0.1 Hz to 10.0 Hz Voltage Noise
0
CH1 p-p
66µV
–20
–30
–40
–50
–60
–70
–80
05428-030
50µV/DIV
RIPPLE REJECTION RATIO (dB)
–10
–90
05428-027
TIME = 1s/DIV
–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. A | Page 13 of 20
1M
ADR440/ADR441/ADR443/ADR444/ADR445
THEORY OF OPERATION
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.
POWER DISSIPATION CONSIDERATIONS
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-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.
TJ and TA are the junction and ambient temperatures,
respectively.
PD is the device power dissipation.
θJA is the device package thermal resistance.
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, users should use the following equation to account for
the temperature effects of increases in power dissipation:
TJ = PD × θJA + TA
where:
BASIC VOLTAGE REFERENCE CONNECTIONS
The ADR44x family requires a 0.1 μF capacitor on the input
and the output for stability. While not required for operation,
a 10 μF capacitor at the input can help with line voltage
transient performance.
VIN
10µF
0.1µF
NC 3
GND
4
8
TP
7
NC
6
VOUT
TOP VIEW
5 TRIM
(Not to Scale)
NOTES
1. NC = NO CONNECT
2. TP = TEST PIN (DO NOT CONNECT)
(1)
where:
0.1µF
Figure 34. Basic Voltage Reference Configuration
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.
ADR44x devices are created by on-chip adjustment of R2
and R3 to achieve the different voltage option at the
reference output.
VIN
I1
I1
ADR44x
VOUT
R2
*
ΔVP
R1
*EXTRA CHANNEL IMPLANT
VOUT = G (ΔVP – R1 × IPTAT)
R3
GND
05428-033
IPTAT
+
2
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
05428-034
TP 1
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 absolute temperature.
The general equation is
VOUT = G (ΔVP − R1 × I PTAT )
(2)
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 made 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. A | Page 14 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
APPLICATIONS
+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
0.1µF
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
+5V
VOUT 6
0.1µF
GND
R1
R2
10kΩ 10kΩ
4
+10V
05428-036
–5V
0.1µF
R3
5kΩ
2
–10V
VIN
VOUT 6
4
R1
100kΩ
NEGATIVE REFERENCE
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 can occur.
Figure 37 shows how to connect the ADR44x and a standard
operational amplifier, such as the OP1177, to provide negative
voltage. This configuration provides two main advantages. First,
it only requires two devices; therefore, it does not require
excessive board space. Second, and more importantly, it does
not require any external resistors. This means the performance
of this circuit does not rely on choosing low temperature
coefficient resistors to ensure accuracy.
+VDD
2
BIPOLAR OUTPUTS
VIN
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
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 Resistor R1 and Resistor R2 (see Figure 36).
They 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.
6
VOUT
GND
4
–VREF
–VDD
05428-037
TRIM 5
GND
0.1µF
05428-035
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
Figure 36. ADR44x Bipolar Outputs
VO = ±0.5%
Figure 37. ADR44x Negative Reference
VOUT is at virtual ground, and the negative reference is taken
directly from the output of the operational amplifier. If the
negative supply voltage is close to the reference output, the
operational amplifier must be dual supply and have low offset
and rail-to-rail capability.
Rev. A | Page 15 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
PROGRAMMABLE VOLTAGE SOURCE
PROGRAMMABLE CURRENT SOURCE
To obtain different voltages than those offered by the ADR44x,
some extra components are needed. In Figure 38, two
potentiometers are used to set the desired voltage, while 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.
It is possible to build a programmable current source using a
setup similar to the programmable voltage source, as shown in
Figure 39. 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.
VCC
0.1µF
2
VIN
RSENSE
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
+VDD
2
VOUT 6
VIN
GND
0.1µF
4
ADJ VREF
AD5259
VOUT 6
ILOAD
R1
R2
10kΩ 10kΩ
05428-038
4
Figure 39. Programmable Current Source
HIGH VOLTAGE FLOATING CURRENT SOURCE
Figure 38. Programmable Voltage Source
For a completely programmable solution, replace the two
potentiometers in Figure 38 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.
Use the circuit in Figure 40 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.
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
+VS
SST111
VISHAY
2
VIN
ITF
I2C
SPI
I2C
SPI
I2C
I 2C
SPI
SPI
SPI
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
VDD1
5.5
5.5
5.5
15
15
5.5
5.5
5.5
5.5
Can also use a negative supply.
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
VOUT 6
OP90
2N3904
GND
4
–VS
Figure 40. Floating Current Source
Adding a negative supply to the operational amplifier allows
the user also 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.
Rev. A | Page 16 of 20
05428-040
GND
05428-039
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
ADR440/ADR441/ADR443/ADR444/ADR445
PRECISION OUTPUT REGULATOR
(BOOSTED REFERENCE)
VIN
2
VIN
15V
VOUT 6
GND
4
COUT
0.1µF
RL
200Ω
–V
CL
1µF
VO
05428-041
CIN
0.1µF
2N7002
ADR440/
ADR441/
ADR443/
ADR444/
ADR445
Figure 41. Boosted Output Reference
Higher current drive capability can be obtained, without
sacrificing accuracy, by using the circuit in Figure 41. 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. A | Page 17 of 20
ADR440/ADR441/ADR443/ADR444/ADR445
OUTLINE DIMENSIONS
5.00 (0.1968)
4.80 (0.1890)
8
5
4.00 (0.1574)
3.80 (0.1497) 1
6.20 (0.2440)
5.80 (0.2284)
4
1.27 (0.0500)
BSC
0.25 (0.0098)
0.10 (0.0040)
0.50 (0.0196)
× 45°
0.25 (0.0099)
1.75 (0.0688)
1.35 (0.0532)
0.51 (0.0201)
COPLANARITY
SEATING 0.31 (0.0122)
0.10
PLANE
8°
0.25 (0.0098) 0° 1.27 (0.0500)
0.40 (0.0157)
0.17 (0.0067)
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 42. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-8)
Dimensions shown in millimeters and (inches)
3.00
BSC
8
3.00
BSC
1
5
4.90
BSC
4
PIN 1
0.65 BSC
1.10 MAX
0.15
0.00
0.38
0.22
COPLANARITY
0.10
0.23
0.08
8°
0°
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MO-187-AA
Figure 43. 8-Lead Mini Small Outline Package [MSOP]
(RM-8)
Dimensions show in millimeters
Rev. A | Page 18 of 20
0.80
0.60
0.40
ADR440/ADR441/ADR443/ADR444/ADR445
ORDERING GUIDE
Model
ADR440ARZ 1
ADR440ARZ-REEL71
ADR440ARMZ1
ADR440ARMZ-REEL71
ADR440BRZ1
ADR440BRZ-REEL71
ADR441ARZ1
ADR441ARZ-REEL71
ADR441ARMZ1
ADR441ARMZ-REEL71
ADR441BRZ1
ADR441BRZ-REEL71
ADR443ARZ1
ADR443ARZ-REEL71
ADR443ARMZ1
ADR443ARMZ-REEL71
ADR443BRZ1
ADR443BRZ-REEL71
ADR444ARZ1
ADR444ARZ-REEL71
ADR444ARMZ1
ADR444ARMZ-REEL71
ADR444BRZ1
ADR444BRZ-REEL71
ADR445ARZ1
ADR445ARZ-REEL71
ADR445ARMZ1
ADR445ARMZ-REEL71
ADR445BRZ1
ADR445BRZ-REEL71
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 = Pb-free part.
Rev. A | Page 19 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
Purchase of licensed I2C components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips I2C Patent
Rights to use these components in an I2C system, provided that the system conforms to the I2C Standard Specification as defined by Philips.
©2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05428-0-9/06(A)
Rev. A | Page 20 of 20