ANALOG DEVICES ADR420, ADR421, ADR423, ADR425 Service Manual

Ultraprecision, Low Noise, 2.048 V/2.500 V/

®

3.00 V/5.00 V XFET

Voltage References

FEATURES

Low noise (0.1 Hz to 10 Hz)

ADR420: 1.75 μV p-p
ADR421: 1.75 μV p-p
ADR423: 2.0 μV p-p

ADR425: 3.4 μV p-p
Low temperature coefficient: 3 ppm/°C
Long-term stability: 50 ppm/1,000 hours
Load regulation: 70 ppm/mA
Line regulation: 35 ppm/V
Low hysteresis: 40 ppm typical
Wide operating range

ADR420: 4 V to 18 V

ADR421: 4.5 V to 18 V

ADR423: 5 V to 18 V

ADR425: 7 V to 18 V
Quiescent current: 0.5 mA maximum
High output current: 10 mA
Wide temperature range: −40°C to +125°C

APPLICATIONS

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

ADR420/ADR421/ADR423/ADR425

PIN CONFIGURATION

TP

1

ADR420/
ADR421/

2

V

IN

ADR423/

ADR425

NIC

3

TOP VIEW

4

GND

(Not to Scale)

NIC = NO INTERNAL CONNECTION

TP = TEST PIN (DO NOT CONNECT)

Figure 1. 8-Lead SOIC, 8-Lead MSOP

GENERAL DESCRIPTION

The ADR42x are a series of ultraprecision, second-generation
eXtra implanted junction FET (XFET) voltage references
featuring low noise, high accuracy, and excellent long-term
stability in SOIC and MSOP footprints.

Patented temperature drift curvature correction technique and
XFET technology minimize nonlinearity of the voltage change
with temperature. The XFET architecture offers superior
accuracy and thermal hysteresis to the band gap references. It
also operates at lower power and lower supply headroom than
the buried Zener references.

The superb noise and the stable and accurate characteristics of
the ADR42x make them ideal for precision conversion
applications such as optical networks and medical equipment.
The ADR42x trim terminal can also be used to adjust the out­put voltage over a ±0.5% range without compromising any
other performance. The ADR42x series voltage references
offer two electrical grades and are specified over the extended
industrial temperature range of −40°C to +125°C. Devices have
8-lead SOIC or 30% smaller, 8-lead MSOP packages.

TP

8

NIC

7

V

6

OUT

5

TRIM

02432-001

ADR42x PRODUCTS

Table 1.

Initial Accuracy

Model

ADR420 2.048 1, 3 0.05, 0.15 3, 10
ADR421 2.50 1, 3 0.04, 0.12 3, 10
ADR423 3.00 1.5, 4 0.04, 0.13 3, 10
ADR425 5.00 2, 6 0.04, 0.12 3, 10

Rev. G

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.

Output Voltage (V

O) mV % Temperature Coefficient (ppm/°C)

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

ADR420/ADR421/ADR423/ADR425

TABLE OF CONTENTS

Features .............................................................................................. 1

Applications....................................................................................... 1

Pin Configuration............................................................................. 1

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

ADR420 Electrical Specifications................................................... 3

ADR421 Electrical Specifications................................................... 4

ADR423 Electrical Specifications................................................... 5

ADR425 Electrical Specifications................................................... 6

Absolute Maximum Ratings............................................................ 7

ESD Caution.................................................................................. 7

Pin Configuration and Function Descriptions............................. 8

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

Parameter Definitions.................................................................... 15

Theory of Operation ...................................................................... 16

Device Power Dissipation Considerations.............................. 16

Basic Voltage Reference Connections...................................... 16

Noise Performance .....................................................................16

Tur n -O n Tim e ............................................................................ 16

REVISION HISTORY

Applications..................................................................................... 17

Output Adjustment .................................................................... 17

Reference for Converters in Optical Network

Control Circuits.......................................................................... 17

A Negative Precision Reference

Without Precision Resistors...................................................... 17

High Voltage Floating Current Source .................................... 18

Kelvin Connections.................................................................... 18

Dual-Polarity References........................................................... 18

Programmable Current Source ................................................ 19

Programmable DAC Reference Voltage.................................. 19

Precision Voltage Reference for Data Converters.................. 20

Precision Boosted Output Regulator....................................... 20

Outline Dimensions ....................................................................... 21

Ordering Guide .......................................................................... 22

6/05—Rev. F to Rev. G

Changes to Table 1............................................................................ 1

Changes to Ordering Guide.......................................................... 22

2/05—Rev. E to Rev. F

Updated Format..................................................................Universal

Updated Outline Dimensions....................................................... 21

Changes to Ordering Guide.......................................................... 22

7/04—Rev. D to Rev. E.

Changes to Ordering Guide............................................................ 5

3/04—Rev. C to Rev. D.

Changes to Table I ............................................................................ 1

Changes to Ordering Guide............................................................ 4

Updated Outline Dimensions....................................................... 16

1/03—Rev. B to Rev. C.

Changed Mini_SOIC to MSOP........................................ Universal

Changes to Ordering Guide.............................................................4

Corrections to Y-axis labels in TPCs 21 and 24 ............................9

Enhancement to Figure 13............................................................ 15

Updated Outline Dimensions....................................................... 16

3/02—Rev. A to Rev. B.

Edits to Ordering Guide...................................................................4

Deletion of Precision Voltage Regulator section........................ 15

Addition of Precision Boosted Output Regulator section ....... 15

Addition of Figure 13..................................................................... 15

Rev. 0 to Rev. A.

Addition of ADR423 and ADR425 to

ADR420/ADR421...............................................................Universal

Rev. G | Page 2 of 24

ADR420/ADR421/ADR423/ADR425

ADR420 ELECTRICAL SPECIFICATIONS

@ VIN = 5.0 V to 15.0 V, TA = 25°C, unless otherwise noted.

Table 2.

Parameter Symbol Conditions Min Typ Max Unit

Output Voltage, A Grade V
Initial Accuracy V

O

OERR

Output Voltage, B Grade V
Initial Accuracy V

O

OERR

Temperature Coefficient A Grade, TCV

O

Temperature Coefficient, B Grade 1 3 ppm/°C
Supply Voltage Headroom VIN – V
Line Regulation

ΔV

O

/ΔV

Load Regulation

ΔVO/ΔI

Quiescent Current I

IN

Voltage Noise eN p-p 0.1 Hz to 10 Hz 1.75 μV p-p
Voltage Noise Density e
Turn-On Settling Time t
Long-Term Stability

Output Voltage Hysteresis V

ΔV

N

R

O

O_HYS

Ripple Rejection Ratio RRR fIN = 10 kHz 75 dB
Short Circuit to GND I

SC

2.045 2.048 2.051 V

−3

−0.15

+3 mV
+0.15 %

2.047 2.048 2.049 V

−1

−0.05

−40°C < TA < +125°C

2 V

O

VIN = 5 V to 18 V 10 35 ppm/V

IN

−40°C < TA < +125°C
I

= 0 mA to 10 mA 70 ppm/mA

LOAD

LOAD

−40°C < TA < +125°C

2 10 ppm°C

+1 mV
+0.05 %

No load 390 500 μA

−40°C < TA < +125°C

600 μA

1 kHz 60 nV/√Hz
10 μs
1,000 hours 50 ppm

40 ppm

27 mA

Rev. G | Page 3 of 24

ADR420/ADR421/ADR423/ADR425

ADR421 ELECTRICAL SPECIFICATIONS

@ VIN = 5.0 V to 15.0 V, TA = 25°C, unless otherwise noted.

Table 3.

Parameter Symbol Conditions Min Typ Max Unit

Output Voltage, A Grade VO 2.497 2.500 2.503 V
Initial Accuracy V

Output Voltage, B Grade VO 2.499 2.500 2.501 V
Initial Accuracy V

Temperature Coefficient, A Grade TCVO
Temperature Coefficient, B Grade 1 3 ppm/°C

Supply Voltage Headroom
Line Regulation

Load Regulation

Quiescent Current IIN No load 390 500 μA

Voltage Noise eN p-p 0.1 Hz to 10 Hz 1.75 μV p-p
Voltage Noise Density eN 1 kHz 80 nV/√Hz
Turn-On Settling Time tR 10 μs
Long-Term Stability

Output Voltage Hysteresis V
Ripple Rejection Ratio RRR fIN = 10 kHz 75 dB
Short Circuit to GND ISC 27 mA

OERR

OERR

V

− VO

IN

ΔV

/ΔVIN

O

ΔV

/ΔI

O

ΔVO

O_HYS

LOAD

+3 mV
+0.12 %

+1 mV
+0.04 %

−40°C < TA < +125°C

−3

−0.12

−1

−0.04

2 10 ppm/°C

2 V
VIN = 5 V to 18 V 10 35 ppm/V

−40°C < TA < +125°C
I

= 0 mA to 10 mA 70 ppm/mA

LOAD

−40°C < TA < +125°C

−40°C < TA < +125°C

600 μA

1,000 hours 50 ppm
40 ppm

Rev. G | Page 4 of 24

ADR420/ADR421/ADR423/ADR425

ADR423 ELECTRICAL SPECIFICATIONS

@ VIN = 5.0 V to 15.0 V, TA = 25°C, unless otherwise noted.

Table 4.

Parameter Symbol Conditions Min Typ Max Unit

Output Voltage, A Grade V
Initial Accuracy V

O

OERR

Output Voltage, B Grade V
Initial Accuracy V

O

OERR

Temperature Coefficient, A Grade TCV

O

Temperature Coefficient, B Grade 1 3 ppm/°C
Supply Voltage Headroom

Line Regulation

V
ΔV

IN

− V
/ΔV

O

O

IN

Load Regulation

ΔV

/ΔI

O

LOAD

Quiescent Current I

IN

Voltage Noise eN p-p 0.1 Hz to 10 Hz 2 μV p-p
Voltage Noise Density e
Turn-On Settling Time t
Long-Term Stability

Output Voltage Hysteresis V

ΔV

N

R

O

O_HYS

Ripple Rejection Ratio RRR fIN = 10 kHz 75 dB
Short Circuit to GND I

SC

2.996 3.000 3.004 V

−4

−0.13

+4 mV
+0.13 %

2.9985 3.000 3.0015 V

−40°C < TA < +125°C

−1.5

−0.04

2 10 ppm/°C

+1.5 mV
+0.04 %

2 V
VIN = 5 V to 18 V 10 35 ppm/V

−40°C < TA < +125°C
I

= 0 mA to 10 mA 70 ppm/mA

LOAD

−40°C < TA < +125°C
No load 390 500 μA

−40°C < TA < +125°C

600 μA

1 kHz 90 nV/√Hz
10 μs
1,000 hours 50 ppm

40 ppm

27 mA

Rev. G | Page 5 of 24

ADR420/ADR421/ADR423/ADR425

ADR425 ELECTRICAL SPECIFICATIONS

@ VIN = 7.0 V to 15.0 V, TA = 25°C, unless otherwise noted.

Table 5.

Parameter Symbol Conditions Min Typ Max Unit

Output Voltage, A Grade V
Initial Accuracy V

O

OERR

Output Voltage, B Grade V
Initial Accuracy V

O

OERR

Temperature Coefficient, A Grade TCV

O

Temperature Coefficient, B Grade 1 3 ppm/°C
Supply Voltage Headroom

Line Regulation

VIN − V
ΔV

/ΔV

O

O

IN

Load Regulation

ΔVO/ΔI

LOAD

Quiescent Current I

IN

Voltage Noise eN p-p 0.1 Hz to 10 Hz 3.4 μV p-p
Voltage Noise Density e
Turn-On Settling Time t
Long-Term Stability ∆V
Output Voltage Hysteresis V

N

R

O

O_HYS

Ripple Rejection Ratio RRR fIN = 10 kHz 75 dB
Short Circuit to GND I

SC

4.994 5.000 5.006 V

−6

−0.12

+6 mV
+0.12 %

4.998 5.000 5.002 V

−40°C < TA < +125°C

−2

−0.04

2 10 ppm/°C

+2 mV
+0.04 %

2 V
VIN = 7 V to 18 V 10 35 ppm/V

−40°C < TA < +125°C
I

= 0 mA to 10 mA 70 ppm/mA

LOAD

−40°C < TA < +125°C
No load 390 500 μA

−40°C < TA < +125°C

600 μA

1 kHz 110 nV/√Hz
10 μs
1,000 hours 50 ppm
40 ppm

27 mA

Rev. G | Page 6 of 24

ADR420/ADR421/ADR423/ADR425

ABSOLUTE MAXIMUM RATINGS

These ratings apply at 25°C, unless otherwise noted.

Table 6.

Parameter Rating

Supply Voltage 18 V
Output Short-Circuit Duration to GND Indefinite
Storage Temperature Range R, RM Packages

−65°C to +150°C

Operating Temperature Range ADR42x −40°C to +125°C
Junction Temperature Range R, RM Packages

−65°C to +150°C

Lead Temperature (Soldering, 60 sec) 300°C

Table 7.

Package Type

1

θ

JA

Unit

8-Lead MSOP (RM) 190 °C/W
8-Lead SOIC (R) 130 °C/W

1

θJA is specified for the worst-case conditions, that is, θJA is specified for

devices soldered in the circuit board for surface-mount packages.

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.

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the
human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.

Rev. G | Page 7 of 24

ADR420/ADR421/ADR423/ADR425

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

TP

1

ADR420/
ADR421/

2

V

IN

ADR423/

ADR425

NIC 3

TOP VIEW

4

GND

(Not to Scale)

NIC = NO INTERNAL CONNECTION

TP = TEST PIN (DO NOT CONNECT)

TP8
NIC7
V

6

OUT

5

TRIM

02432-002

Figure 2. Pin Configuration for 8-Lead SOIC

Table 8. Pin Function Descriptions

Pin No. Mnemonic Description

1, 8 TP

Test Pin. There are actual connections in TP pins but they are reserved for factory testing purposes. Users should not
connect anything to TP pins; otherwise, the device may not function properly.

2 V

IN

Input Voltage.
3, 7 NIC No Internal Connect. NICs have no internal connections.
4 GND Ground Pin = 0 V.
5 TRIM

Trim Terminal. It can be used to adjust the output voltage over a ±0.5% range without affecting the temperature

coefficient.
6 V

OUT

Output Voltage.

TP

1

ADR420/
ADR421/

2

V

IN

ADR423/

ADR425

NIC 3

TOP VIEW

4

GND

(Not to Scale)

NIC = NO INTERNAL CONNECTION

TP = TEST PIN (DO NOT CONNECT)

TP8
NIC7
V

6

OUT

5

TRIM

02432-003

Figure 3. Pin Configuration for 8-Lead MSOP

Rev. G | Page 8 of 24