ANALOG DEVICES ADR 441 BRZ Datasheet

Ultralow Noise, LDO XFET Voltage

References with Current Sink and Source

FEATURES

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: (V
High output source and sink current

+10 mA and −5 mA, respectively
Wide temperature range: −40°C to +125°C

APPLICATIONS

Precision data acquisition systems
High resolution data converters
Battery-powered instrumentation
Portable medical instruments
Industrial process control systems
Precision instruments
Optical control circuits

+ 500 mV) to 18 V

OUT

ADR440/ADR441/ADR443/ADR444/ADR445

PIN CONFIGURATIONS

ADR440/

TP

1

ADR441/

2

ADR443/

V

IN

ADR444/

NC

3

ADR445

TOP VIEW

4

GND

(Not to Scale)

NOTES

1. NC = NO CONNECT

2. TP = TEST P IN (DO NOT CO NNECT)

Figure 1. 8-Lead SOIC_N (R-Suffix)

ADR440/

1

TP

ADR441/
ADR443/

V

2

IN

ADR444/

3

NC

ADR445

GND

NOTES

1. NC = NO CONNECT

2. TP = TEST P IN (DO NOT CONNECT)

Figure 2. 8-Lead MSOP (RM-Suffix)

TOP VIEW

4

(Not to S cal e)

TP

8

7

NC
V

6

OUT

5

TRIM

05428-001

8

TP
NC

7

6

V

OUT

TRIM

5

05428-002

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.

Rev. E

Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
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.

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

Output
Voltage
(V)

Initial
Accuracy
(mV)

Temperature
Coefficient
(ppm/°C)

ADR440A 2.048 ±3 10
ADR440B 2.048 ±1 3
ADR441A 2.500 ±3 10
ADR441B 2.500 ±1 3
ADR443A 3.000 ±4 10
ADR443B 3.000 ±1.2 3
ADR444A 4.096 ±5 10
ADR444B 4.096 ±1.6 3
ADR445A 5.000 ±6 10
ADR445B 5.000 ±2 3

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©2005–2010 Analog Devices, Inc. All rights reserved.

ADR440/ADR441/ADR443/ADR444/ADR445

TABLE OF CONTENTS

Features.............................................................................................. 1

Applications....................................................................................... 1

Pin Configurations ........................................................................... 1

General Description ......................................................................... 1

Revision History ............................................................................... 2

Specifications..................................................................................... 3

ADR440 Electrical Characteristics............................................. 3

ADR441 Electrical Characteristics............................................. 4

ADR443 Electrical Characteristics............................................. 5

ADR444 Electrical Characteristics............................................. 6

ADR445 Electrical Characteristics............................................. 7

Absolute Maximum Ratings............................................................ 8

Thermal Resistance ...................................................................... 8

ESD Caution.................................................................................. 8

Typical Performance Characteristics ............................................. 9

Theory of Operation ...................................................................... 14

Power Dissipation Considerations........................................... 14

Basic Voltage Reference Connections ..................................... 14

Noise Performance..................................................................... 14

Turn-On Time ............................................................................ 14

Applications Information.............................................................. 15

Output Adjustment.................................................................... 15

Bipolar Outputs.......................................................................... 15

Programmable Voltage Source ................................................. 15

Programmable Current Source ................................................ 16

High Voltage Floating Current Source.................................... 16

Precision Output Regulator (Boosted Reference)................. 16

Outline Dimensions....................................................................... 17

Ordering Guide .......................................................................... 18

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

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

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

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 = C

Table 2.

Parameter Symbol Conditions Min Typ Max Unit

OUTPUT VOLTAGE VO

A Grade

B Grade

INITIAL ACCURACY V

A Grade

0.15 %

B Grade 1 mV

0.05 %
TEMPERATURE DRIFT TCVO

A Grade −40°C < TA < +125°C 2 10 ppm/°C

B Grade −40°C < TA < +125°C 1 3 ppm/°C

LINE REGULATION ΔVO/ΔVIN −40°C < TA < +125°C −20 +10 +20 ppm/V
LOAD REGULATION ΔVO/ΔI

ΔVO/ΔI

QUIESCENT CURRENT IIN No load, −40°C < TA < +125°C 3 3.75 mA
VOLTAGE NOISE eN p-p 0.1 Hz to 10 Hz 1 μV p-p
VOLTAGE NOISE DENSITY eN 1 kHz 45 nV/√Hz
TURN-ON SETTLING TIME tR 10 μs
LONG-TERM STABILITY1 V
OUTPUT VOLTAGE HYSTERESIS V
RIPPLE REJECTION RATIO RRR fIN = 1 kHz −80 dB
SHORT CIRCUIT TO GND ISC 27 mA
SUPPLY VOLTAGE OPERATING RANGE VIN 3 18 V
SUPPLY VOLTAGE HEADROOM VIN − VO 500 mV

1

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.

= 0.1 µF, unless otherwise noted.

OUT

OERR

LOAD

2.045 2.048 2.051 V

2.047 2.048 2.049 V

3 mV

= 0 mA to 10 mA, VIN = 3.5 V,

I

LOAD

−40°C < T

LOAD

= 0 mA to −5 mA, VIN = 3.5 V,

I

LOAD

−40°C < T

1000 hours 50 ppm

O

70 ppm

O_HYS

< +125°C

A

< +125°C

A

−50 +50 ppm/mA

−50 +50 ppm/mA

Rev. E | Page 3 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

ADR441 ELECTRICAL CHARACTERISTICS

VIN = 3 V to 18 V, TA = 25°C, CIN = C

Table 3.

Parameter Symbol Conditions Min Typ Max Unit

OUTPUT VOLTAGE VO

A Grade
B Grade

INITIAL ACCURACY V

A Grade

0.12 %
B Grade 1 mV

0.04 %
TEMPERATURE DRIFT TCVO

A Grade −40°C < TA < +125°C 2 10 ppm/°C

B Grade −40°C < TA < +125°C 1 3 ppm/°C
LINE REGULATION ΔVO/ΔVIN −40°C < TA < +125°C 10 20 ppm/V
LOAD REGULATION ΔVO/ΔI

ΔVO/ΔI

QUIESCENT CURRENT IIN No load, −40°C < TA < +125°C 3 3.75 mA
VOLTAGE NOISE eN p-p 0.1 Hz to 10 Hz 1.2 μV p-p
VOLTAGE NOISE DENSITY eN 1 kHz 48 nV/√Hz
TURN-ON SETTLING TIME tR 10 μs
LONG-TERM STABILITY1 V
OUTPUT VOLTAGE HYSTERESIS V
RIPPLE REJECTION RATIO RRR fIN = 1 kHz −80 dB
SHORT CIRCUIT TO GND ISC 27 mA
SUPPLY VOLTAGE OPERATING RANGE VIN 3 18 V
SUPPLY VOLTAGE HEADROOM VIN − VO 500 mV

1

The long-term stability specification is noncumulative. The drift in subsequent 1000-hour period is significantly lower than in the first 1000-hour period.

= 0.1 µF, unless otherwise noted.

OUT

OERR

LOAD

2.497 2.500 2.503 V

2.499 2.500 2.501 V

3 mV

= 0 mA to 10 mA, VIN = 4 V,

I

LOAD

−40°C < T

LOAD

= 0 mA to −5 mA, VIN = 4 V,

I

LOAD

−40°C < T

1000 hours 50 ppm

O

70 ppm

O_HYS

< +125°C

A

< +125°C

A

−50 +50 ppm/mA

−50 +50 ppm/mA

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 = C

Table 4.

Parameter Symbol Conditions Min Typ Max Unit

OUTPUT VOLTAGE VO

A Grade
B Grade

INITIAL ACCURACY V

A Grade

0.13 %
B Grade 1.2 mV

0.04 %
TEMPERATURE DRIFT TCVO

A Grade −40°C < TA < +125°C 2 10 ppm/°C

B Grade −40°C < TA < +125°C 1 3 ppm/°C
LINE REGULATION ΔVO/ΔVIN −40°C < TA < +125°C 10 20 ppm/V
LOAD REGULATION ΔVO/ΔI

ΔVO/ΔI

QUIESCENT CURRENT IIN No load, −40°C < TA < +125°C 3 3.75 mA
VOLTAGE NOISE eN p-p 0.1 Hz to 10 Hz 1.4 μV p-p
VOLTAGE NOISE DENSITY eN 1 kHz 57.6 nV/√Hz
TURN-ON SETTLING TIME tR 10 μs
LONG-TERM STABILITY1 V
OUTPUT VOLTAGE HYSTERESIS V
RIPPLE REJECTION RATIO RRR fIN = 1 kHz −80 dB
SHORT CIRCUIT TO GND ISC 27 mA
SUPPLY VOLTAGE OPERATING RANGE VIN 3.5 18 V
SUPPLY VOLTAGE HEADROOM VIN − VO 500 mV

1

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.

= 0.1 µF, unless otherwise noted.

OUT

OERR

LOAD

2.996 3.000 3.004 V

2.9988 3.000 3.0012 V

4 mV

= 0 mA to 10 mA, VIN = 5 V,

I

LOAD

−40°C < T

LOAD

= 0 mA to −5 mA, VIN = 5 V,

I

LOAD

−40°C < T

1000 hours 50 ppm

O

70 ppm

O_HYS

< +125°C

A

< +125°C

A

−50 +50 ppm/mA

−50 +50 ppm/mA

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 = C

Table 5.

Parameter Symbol Conditions Min Typ Max Unit

OUTPUT VOLTAGE VO

A Grade
B Grade

INITIAL ACCURACY V

A Grade

0.13 %
B Grade 1.6 mV

0.04 %
TEMPERATURE DRIFT TCVO

A Grade −40°C < TA < +125°C 2 10 ppm/°C

B Grade −40°C < TA < +125°C 1 3 ppm/°C
LINE REGULATION ΔVO/ΔVIN −40°C < TA < +125°C 10 20 ppm/V
LOAD REGULATION ΔVO/ΔI

ΔVO/ΔI

QUIESCENT CURRENT IIN No load, −40°C < TA < +125°C 3 3.75 mA
VOLTAGE NOISE eN p-p 0.1 Hz to 10 Hz 1.8 μV p-p
VOLTAGE NOISE DENSITY eN 1 kHz 78.6 nV/√Hz
TURN-ON SETTLING TIME tR 10 μs
LONG-TERM STABILITY1 V
OUTPUT VOLTAGE HYSTERESIS V
RIPPLE REJECTION RATIO RRR fIN = 1 kHz −80 dB
SHORT CIRCUIT TO GND ISC 27 mA
SUPPLY VOLTAGE OPERATING RANGE VIN 4.6 18 V
SUPPLY VOLTAGE HEADROOM VIN − VO 500 mV

1

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.

= 0.1 µF, unless otherwise noted.

OUT

OERR

1000 hours 50 ppm

O

70 ppm

O_HYS

4.091 4.096 4.101 V

4.0944 4.096 4.0976 V

5 mV

LOAD

LOAD

= 0 mA to 10 mA, VIN = 5.5 V,

I

LOAD

−40°C < T
I

LOAD

−40°C < T

< +125°C

A

= 0 mA to −5 mA, VIN = 5.5 V,

< +125°C

A

−50 +50 ppm/mA

−50 +50 ppm/mA

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 = C

Table 6.

Parameter Symbol Conditions Min Typ Max Unit

OUTPUT VOLTAGE VO

A Grade
B Grade

INITIAL ACCURACY V

A Grade

0.12 %
B Grade 2 mV

0.04 %
TEMPERATURE DRIFT TCVO

A Grade −40°C < TA < +125°C 2 10 ppm/°C

B Grade −40°C < TA < +125°C 1 3 ppm/°C
LINE REGULATION ΔVO/ΔVIN −40°C < TA < +125°C 10 20 ppm/V
LOAD REGULATION ΔVO/ΔI

ΔVO/ΔI

QUIESCENT CURRENT IIN No load, −40°C < TA < +125°C 3 3.75 mA
VOLTAGE NOISE eN p-p 0.1 Hz to 10 Hz 2.25 μV p-p
VOLTAGE NOISE DENSITY eN 1 kHz 90 nV/√Hz
TURN-ON SETTLING TIME tR 10 μs
LONG-TERM STABILITY1 V
OUTPUT VOLTAGE HYSTERESIS V
RIPPLE REJECTION RATIO RRR fIN = 1 kHz –80 dB
SHORT CIRCUIT TO GND ISC 27 mA
SUPPLY VOLTAGE OPERATING RANGE VIN 5.5 18 V
SUPPLY VOLTAGE HEADROOM VIN − VO 500 mV

1

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.

= 0.1 µF, unless otherwise noted.

OUT

OERR

LOAD

4.994 5.000 5.006 V

4.998 5.000 5.002 V

6 mV

= 0 mA to 10 mA, VIN = 6.5 V,

I

LOAD

−40°C < T

LOAD

= 0 mA to −5 mA, VIN = 6.5 V,

I

LOAD

−40°C < T

1000 hours 50 ppm

O

70 ppm

O_HYS

< +125°C

A

< +125°C

A

−50 +50 ppm/mA

−50 +50 ppm/mA

Rev. E | Page 7 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

ABSOLUTE MAXIMUM RATINGS

TA = 25°C, unless otherwise noted.

Table 7.

Parameter Rating

Supply Voltage 20 V
Output Short-Circuit Duration to GND Indefinite
Storage Temperature Range −65°C to +125°C
Operating Temperature Range −40°C to +125°C
Junction Temperature Range −65°C to +150°C
Lead Temperature, Soldering (60 sec) 300°C

Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.

THERMAL RESISTANCE

θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.

Table 8. Thermal Resistance

Package Type θJA θJC Unit

8-Lead SOIC (R-Suffix) 130 43 °C/W
8-Lead MSOP (RM-Suffix) 132.5 43.9 °C/W

ESD CAUTION

Rev. E | Page 8 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

TYPICAL PERFORMANCE CHARACTERISTICS

VIN = 7 V, TA = 25°C, CIN = C

2.051

= 0.1 µF, unless otherwise noted.

OUT

4.0980

2.050

2.049

2.048

2.047

OUTPUT VOLTAGE (V)

2.046

2.045
–40 –20 0 20 100806040 120

TEMPERATURE (°C)

Figure 3. ADR440 Output Voltage vs. Temperature

2.5020

2.5015

2.5010

2.5005

2.5000

OUTPUT VOLTAGE (V)

4.0975

4.0970

4.0965

4.0960

4.0955

OUTPUT VOLTAGE (V)

4.0950

4.0945

05428-042

4.0940
–40 5–10–25 503520 110958065 125

DEVICE 1

DEVICE 3

TEMPERATURE (°C)

DEVICE 2

05428-005

Figure 6. ADR444 Output Voltage vs. Temperature

5.006

5.004

5.002

5.000

4.998

OUTPUT VOLTAGE (V)

2.4995

2.4990
–40 5–10–25 503520 110958065 125

TEMPERATURE (°C)

Figure 4. ADR441 Output Voltage vs. Temperature

3.0020

3.0015

3.0010

3.0005

3.0000

2.9995

OUTPUT VOLTAGE (V)

2.9990

2.9985

2.9980
–40 5–10–25 503520 110958065 125

DEVICE 1

DEVICE 2

DEVICE 3

TEMPERATURE (°C)

Figure 5. ADR443 Output Voltage vs. Temperature

4.996

05428-003

4.994
–40 –20 0 20 100806040 120

TEMPERATURE (°C)

05428-043

Figure 7. ADR445 Output Voltage vs. Temperature

4.0

3.5
+125°C

–40°C

+25°C

6

05428-006

3.0

SUPPLY CURRENT (mA)

2.5

05428-004

2.0

46 10811412 18

INPUT VOLTAGE (V)

Figure 8. ADR441 Supply Current vs. Input Voltage

Rev. E | Page 9 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

A

A

4.0

10

3.5

3.0

SUPPLY CURRENT (mA)

2.5

2.0
–40 5–10–25 503520 110958065 125

TEMPERATURE (°C)

Figure 9. ADR441 Supply Current vs. Temperature

3.5

3.4

3.3

3.2

3.1

3.0

2.9

2.8

SUPPLY CURRENT (mA)

2.7

2.6

2.5

5.3 9.37.3 13.311.3 17.315.3 19.3

INPUT VOLTAGE (V)

+125°C

+25°C

–40°C

Figure 10. ADR445 Supply Current vs. Input Voltage

8

6

TION (ppm/V)

4

LINE REGUL

2

05428-007

0

–40 5–10–25 503520 110958065 125

TEMPERATURE (°C)

05428-010

Figure 12. ADR441 Line Regulation vs. Temperature

60

I

= 0mA TO 10mA

LOAD

55

VIN = 18V

50

TION (ppm/mA)

45

VIN = 6V

40

LOAD REGUL

35

05428-008

30

–40 5–10–25 503520 110958065 125

TEMPERATURE (°C)

05428-011

Figure 13. ADR441 Load Regulation vs. Temperature

3.25

3.15

3.05

2.95

SUPPLY CURRENT (mA)

2.85

2.75
–40 5–10–25 503520 110958065 125

TEMPERATURE (°C)

Figure 11. ADR445 Supply Current vs. Temperature

05428-009

Rev. E | Page 10 of 20

7

6

5

4

3

2

LINE REGUL ATION (ppm/V)

1

0

–40 5–10–25 503520 110958065 125

TEMPERATURE (°C)

Figure 14. ADR445 Line Regulation vs. Temperature

05428-012

ADR440/ADR441/ADR443/ADR444/ADR445

A

A

A

50

VIN = 6V

40

30

20
10

TION (ppm/mA)

–10

–20

LOAD REGUL

–30
–40
–50

I

= 0mA TO +10mA

LOAD

0

I

= 0mA TO –5mA

LOAD

–40 5–10–25 503520 110958065 125

TEMPERATURE (°C)

Figure 15. ADR445 Load Regulation vs. Temperature

05428-013

1.0

0.9

0.8

0.7

0.6

L VOLTAGE (V)

0.5

0.4

0.3

DIFFERENTI

0.2

0.1
0

–5 0 5 10

LOAD CURRENT (mA)

+125°C

Figure 18. ADR445 Minimum Input/Output

Differential Voltage vs. Load Current

+25°C

–40°C

05428-016

0.7

0.6

0.5

0.4

L VOLTAGE (V)

0.3

0.2

DIFFERENTI

0.1

0

–10 –5 0 5 10

LOAD CURRENT (mA)

+125°C

+25°C

Figure 16. ADR441 Minimum Input/Output

Differential Voltage vs. Load Current

0.5
NO LOAD

0.4

0.3

0.2

–40°C

0.5
NO LOAD

0.4

0.3

0.2

MINIMUM HEADROOM (V)

0.1

05428-014

0

–40 5–10–25 503520 110958065 125

TEMPERATURE (°C)

05428-017

Figure 19. ADR445 Minimum Headroom vs. Temperature

CIN = C

OUT

VIN = 5V/DIV

= 0.1µF

MINIMUM HEADROOM (V)

0.1

0

–40 5–10–25 503520 110958065 125

TEMPERATURE (°C)

05428-015

Figure 17. ADR441 Minimum Headroom vs. Temperature

Rev. E | Page 11 of 20

V

= 1V/DIV

OUT

Figure 20. ADR441 Turn-On Response

TIME = 10µs/DIV

05428-018

ADR440/ADR441/ADR443/ADR444/ADR445

CIN = C

= 0.1µF

OUT

TIME = 200µs/DIV

Figure 21. ADR441 Turn-Off Response

CIN = 0.1µF
C

= 10µF

OUT

VIN = 5V/DIV

V

= 1V/DIV

OUT

VIN = 5V/DIV

V

= 1V/DIV

OUT

CIN = 0.1µF
C

= 10µF

OUT

LOAD OFF

05428-019

TIME = 200µs/DIV

LOAD ON

5mV/DIV

05428-023

Figure 24. ADR441 Load Transient Response

CIN = C

= 0.1µF

OUT

LOAD OFF L OAD ON

5mV/DIV

TIME = 200µs/DIV

Figure 22. ADR441 Turn-On Response

CIN = 0.1µF
C

= 10µF

OUT

4V

TIME = 100µs/DIV

Figure 23. ADR441 Line Transient Response

2V/DIV

2mV/DIV

05428-020

TIME = 2 00µs/DIV

05428-022

Figure 25. ADR441 Load Transient Response

1µV/DIV

CH 1 p-p

1.18µV

TIME = 1s/DIV

05428-021

05428-024

Figure 26. ADR441 0.1 Hz to 10.0 Hz Voltage Noise

Rev. E | Page 12 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

A

16

14

12

50µV/DIV

CH 1 p-p
49µV

10

8

6

NUMBER OF PARTS

4

TIME = 1s/DIV

Figure 27. ADR441 10 Hz to 10 kHz Voltage Noise

1µV/DIV

TIME = 1s/DIV

Figure 28. ADR445 0.1 Hz to 10.0 Hz Voltage Noise

50µV/DIV

TIME = 1s/DIV

Figure 29. ADR445 10 Hz to 10 kHz Voltage Noise

05428-025

CH 1 p-p

2.24µV

05428-026

CH 1 p-p
66µV

05428-027

2

0

–90

–70

–150

–130

–110

–50

103050

–10

–30

DEVIATIO N (ppm)

90

70

110

05428-028

150

130

Figure 30. ADR441 Typical Output Voltage Hysteresis

10

9

8

7

6
5

4

3

OUTPUT IMPEDANCE (Ω)

2
1
0

FREQUENCY (Hz)

ADR445

ADR443

ADR441

100k10k1k10010

05428-029

Figure 31. Output Impedance vs. Frequency

0

–10

–20

–30

TIO (dB)

–40

–50

–60

–70

–80

RIPPLE REJE CTION R

–90

–100

FREQUENCY (Hz)

100k 1M10k1k100

05428-030

Figure 32. Ripple Rejection Ratio vs. Frequency

Rev. E | Page 13 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

V

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.

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.

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

V

= G (VP − R1 × I

OUT

) (1)

PTAT

where:
G is the gain of the reciprocal of the divider ratio.
∆V

is the difference in pinch-off voltage between the two JFETs.

P

I

is the positive temperature coefficient correction current.

PTAT

ADR44x devices are created by on-chip adjustment of R2
and R3 to achieve the different voltage options at the
reference output.

IN

I

PTAT

I

I

1

1

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:

T

= PD × θJA + TA (2)

J

where:

T

and TA are the junction and ambient temperatures,

J

respectively.

P

is the device power dissipation.

D

is the device package thermal resistance.

θ

JA

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.

ADR440/

TP

1

NC

GND

ADR441/
ADR443/

2

ADR444/

3

ADR445

TOP VIEW

4

(Not to Scale)

V

IN

+

10µF

0.1µF

NOTES

1. NC = NO CONNECT

2. TP = TEST PIN (DO NOT CONNECT)

Figure 34. Basic Voltage Reference Configuration

TP

8

7

NC
V

OUT

6

TRIM

5

0.1µF

05428-034

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 2pole high-pass filter with a corner frequency at 0.1 Hz and a
2pole low-pass filter with a corner frequency at 10.0 Hz.

ADR44x

*

∆V

P

R1

V

OUT

R2

R3

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

*EXTRA CHANNEL IMPLANT

= G (∆VP – R1 × I

V

OUT

PTAT

)

Figure 33. Simplified Schematic Device

GND

05428-033

chip to stabilize. Figure 20 and Figure 21 show the turn-on and
turn-off settling times for the ADR441.

Rev. E | Page 14 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

V

V

APPLICATIONS INFORMATION

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. R
be sufficiently large so that the maximum output current from
the ADR44x is not exceeded.

0.1µF

2

V

IN

V

OUT

ADR440/
ADR441/
ADR443/
ADR444/
ADR445

TRIM

GND

4

6

5

R1

100kΩ

0.1µF

R

P

10kΩ
R2

1kΩ

VO = ±0.5%

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.

BIPOLAR OUTPUTS

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.

should

P

05428-035

+

DD

2

V

IN

ADR440/
ADR441/
ADR443/

0.1µF

ADR444/

ADR445

V

OUT

GND

4

6

0.1µF

R3

5kΩ

R1
10kΩ

10kΩ

+10V

–10V

+5V

R2

–5V

05428-036

Figure 36. ADR44x Bipolar Outputs

PROGRAMMABLE VOLTAGE SOURCE

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 V
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.

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 I
interface. These interfaces set the position of the wiper on both
potentiometers and allow the output voltage to be set. Ta ble 9
lists compatible Analog Devices digital potentiometers.

and GND, with its wiper connected to the

OUT

+

DD

2

V

IN

ADR440/
ADR441/
ADR443/
ADR444/

ADR445

GND

4

6

V

OUT

R1

R2

10kΩ

10kΩ

Figure 37. Programmable Voltage Source

ADJ V

REF

2

C

05428-038

Rev. E | Page 15 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

V

V

V

Table 9. Digital Potentiometer Parts

V
(V)

1

DD

Part No.

No. of
Channels

No. of
Positions ITF R (kΩ)

AD5251 2.00 64.00 I2C 1, 10, 50, 100 5.5
AD5207 2.00 256.00 SPI 10, 50, 100 5.5
AD5242 2.00 256.00 I2C 10, 100, 1M 5.5
AD5262 2.00 256.00 SPI 20, 50, 200 15
AD5282 2.00 256.00 I2C 20, 50, 100 15
AD5252 2.00 256.00 I2C 1, 10, 50, 100 5.5
AD5232 2.00 256.00 SPI 10, 50, 100 5.5
AD5235 2.00 1024.00 SPI 25, 250 5.5
ADN2850 2.00 1024.00 SPI 25, 250 5.5

1

Can also use a negative supply.

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.

PROGRAMMABLE 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.

CC

0.1µF

2

V

IN

ADR440/
ADR441/
ADR443/
ADR444/

ADR445

V

OUT

6

GND

4

0.1µF

AD5259

Figure 38. Programmable Current Source

I

LOAD

R

SENSE

05428-039

HIGH VOLTAGE FLOATING CURRENT SOURCE

Use the c ircu it 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.

+

S

SST111

VISHAY

2

V

IN

ADR440/
ADR441/
ADR443/
ADR444/

ADR445

V

OUT

6

GND

4

OP90

Figure 39. Floating Current Source

2N3904

–V

S

05428-040

PRECISION OUTPUT REGULATOR (BOOSTED REFERENCE)

IN

C

IN

0.1µF

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
V

to equal the V

O

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 V
capacitive loading.

2

V

IN

ADR440/
ADR441/
ADR443/
ADR444/
ADR445

V

OUT

GND

4

6

C

0.1µF

15V

OUT

–V

Figure 40. Boosted Output Reference

. Current is then drawn from VIN, allowing

REF

to aid with

O

200Ω

2N7002

R

L

C
1µF

V

O

L

5428-041

Rev. E | Page 16 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

OUTLINE DIMENSIONS

5.00(0.1968)

4.80(0.1890)

4.00 (0.1574)

3.80 (0.1497)

0.25 (0.0098)

0.10 (0.0040)

COPLANARITY

0.10

CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLYAND ARE NOT APPROPRIATE FOR USE IN DESIGN.

85

1

1.27 (0.0500)

SEATING

PLANE

COMPLIANT TO JEDEC STANDARDS MS-012-AA

BSC

6.20 (0.2441)

5.80 (0.2284)

4

1.75 (0.0688)

1.35 (0.0532)

0.51 (0.0201)

0.31 (0.0122)

8°
0°

0.25 (0.0098)

0.17 (0.0067)

0.50 (0.0196)

0.25 (0.0099)

1.27 (0.0500)

0.40 (0.0157)

45°

012407-A

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

5

3.20

3.00

2.80

PIN 1

IDENTIFIER

0.95

0.85

0.75

0.15

0.05

COPLANARITY

1

0.65 BSC

0.10

COMPLIANT TO JEDEC STANDARDS MO-187-AA

Figure 42. 8-Lead Mini Small Outline Package [MSOP]

5.15

4.90

4.65

4

15° MAX

6°
0°

0.23

0.09

0.40

0.25

1.10 MAX

(RM-8)

Dimensions show in millimeters

0.80

0.55

0.40

10-07-2009-B

Rev. E | Page 17 of 20

ADR440/ADR441/ADR443/ADR444/ADR445

ORDERING GUIDE

Initial

Output

Model1

ADR440ARZ 2.048 3 0.15 10 8-Lead SOIC_N –40°C to +125°C R-8
ADR440ARZ-REEL7 2.048 3 0.15 10 8-Lead SOIC_N –40°C to +125°C R-8
ADR440ARMZ 2.048 3 0.15 10 8-Lead MSOP R01 –40°C to +125°C RM-8
ADR440ARMZ-REEL7 2.048 3 0.15 10 8-Lead MSOP R01 –40°C to +125°C RM-8
ADR440BRZ 2.048 1 0.05 3 8-Lead SOIC_N –40°C to +125°C R-8
ADR440BRZ-REEL7 2.048 1 0.05 3 8-Lead SOIC_N –40°C to +125°C R-8
ADR441ARZ 2.500 3 0.12 10 8-Lead SOIC_N –40°C to +125°C R-8
ADR441ARZ-REEL7 2.500 3 0.12 10 8-Lead SOIC_N –40°C to +125°C R-8
ADR441ARMZ 2.500 3 0.12 10 8-Lead MSOP R02 –40°C to +125°C RM-8
ADR441ARMZ-REEL7 2.500 3 0.12 10 8-Lead MSOP R02 –40°C to +125°C RM-8
ADR441BRZ 2.500 1 0.04 3 8-Lead SOIC_N –40°C to +125°C R-8
ADR441BRZ-REEL7 2.500 1 0.04 3 8-Lead SOIC_N –40°C to +125°C R-8
ADR443ARZ 3.000 4 0.13 10 8-Lead SOIC_N –40°C to +125°C R-8
ADR443ARZ-REEL7 3.000 4 0.13 10 8-Lead SOIC_N –40°C to +125°C R-8
ADR443ARMZ 3.000 4 0.13 10 8-Lead MSOP R03 –40°C to +125°C RM-8
ADR443ARMZ-REEL7 3.000 4 0.13 10 8-Lead MSOP R03 –40°C to +125°C RM-8
ADR443BRZ 3.000 1.2 0.04 3 8-Lead SOIC_N –40°C to +125°C R-8
ADR443BRZ-REEL7 3.000 1.2 0.04 3 8-Lead SOIC_N –40°C to +125°C R-8
ADR444ARZ 4.096 5 0.13 10 8-Lead SOIC_N –40°C to +125°C R-8
ADR444ARZ-REEL7 4.096 5 0.13 10 8-Lead SOIC_N –40°C to +125°C R-8
ADR444ARMZ 4.096 5 0.13 10 8-Lead MSOP R04 –40°C to +125°C RM-8
ADR444ARMZ-REEL7 4.096 5 0.13 10 8-Lead MSOP R04 –40°C to +125°C RM-8
ADR444BRZ 4.096 1.6 0.04 3 8-Lead SOIC_N –40°C to +125°C R-8
ADR444BRZ-REEL7 4.096 1.6 0.04 3 8-Lead SOIC_N –40°C to +125°C R-8
ADR445ARZ 5.000 6 0.12 10 8-Lead SOIC_N –40°C to +125°C R-8
ADR445ARZ-REEL7 5.000 6 0.12 10 8-Lead SOIC_N –40°C to +125°C R-8
ADR445ARMZ 5.000 6 0.12 10 8-Lead MSOP R05 –40°C to +125°C RM-8
ADR445ARMZ-REEL7 5.000 6 0.12 10 8-Lead MSOP R05 –40°C to +125°C RM-8
ADR445BRZ 5.000 2 0.04 3 8-Lead SOIC_N –40°C to +125°C R-8
ADR445BRZ-REEL7 5.000 2 0.04 3 8-Lead SOIC_N –40°C to +125°C R-8

1

Z = RoHS Compliant Part.

Voltage (V)

Accuracy

±mV %

Temperature
Coefficient
Package (ppm/°C)

Package
Description Branding

Temperature
Range

Package
Option

Rev. E | Page 18 of 20

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