Analog Devices AD629 Datasheet

High Common-Mode Voltage

a

FEATURES
Improved Replacement for:

INA117P and INA117KU
ⴞ270 V Common-Mode Voltage Range
Input Protection to:

ⴞ500 V Common Mode

ⴞ500 V Differential
Wide Power Supply Range (ⴞ2.5 V to ⴞ18 V)
ⴞ10 V Output Swing on ⴞ12 V Supply

1 mA Max Power Supply Current

HIGH ACCURACY DC PERFORMANCE
3 ppm Max Gain Nonlinearity
20 ␮V/ⴗC Max Offset Drift (AD629A)
10 ␮V/ⴗC Max Offset Drift (AD629B)
10 ppm/ⴗC Max Gain Drift

EXCELLENT AC SPECIFICATIONS
77 dB Min CMRR @ 500 Hz (AD629A)
86 dB Min CMRR @ 500 Hz (AD629B)
500 kHz Bandwidth

APPLICATIONS
High Voltage Current Sensing
Battery Cell Voltage Monitor
Power Supply Current Monitor
Motor Control
Isolation

Difference Amplifier

AD629

FUNCTIONAL BLOCK DIAGRAM

8-Lead Plastic Mini-DIP (N) and SOIC (R) Packages

REF(–)

–V

–IN

+IN

380k⍀

2

380k⍀

3

4

S

21.1k⍀

1

GENERAL DESCRIPTION

The AD629 is a difference amplifier with a very high input
common-mode voltage range. It is a precision device that
allows the user to accurately measure differential signals in the
presence of high common-mode voltages up to ±270 V.

The AD629 can replace costly isolation amplifiers in applications
that do not require galvanic isolation. The device will operate
over a ±270 V common-mode voltage range and has inputs
that are protected from common-mode or differential mode
transients up to ±500 V.

The AD629 has low offset, low offset drift, low gain error drift,
as well as low common-mode rejection drift, and excellent CMRR
over a wide frequency range.

The AD629 is available in low-cost, plastic 8-lead DIP and
SOIC packages. For all packages and grades, performance is
guaranteed over the entire industrial temperature range from
–40°C to +85°C.

380k⍀

20k⍀

AD629

NC = NO CONNECT

NC

8

7

+V

6

OUTPUT

5

REF(+)

S

100

95

90

85

80

75

70

65

60

COMMON-MODE REJECTION RATIO – dB

55

50

20 100

FREQUENCY – Hz

1k 10k 20k

Figure 1. Common-Mode Rejection Ratio vs. Frequency

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
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.

2mV/DIV

OUTPUT ERROR – 2mV/DIV

60V/DIV

–240 –120

COMMON-MODE VOLTAGE – Volts

0 120 240

Figure 2. Common-Mode Operating Range. Error Voltage
vs. Input Common-Mode Voltage

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Tel: [phone] World Wide Web Site: http://www.analog.com
Fax: [phone] © Analog Devices, Inc., 2000

AD629–SPECIFICATIONS

(TA = 25ⴗC, VS = ⴞ15 V unless otherwise noted)

AD629A AD629B

Parameter Condition Min Typ Max Min Typ Max Unit

GAIN V

Nominal Gain 11V/V
Gain Error 0.01 0.05 0.01 0.03 %
Gain Nonlinearity 4 10 4 10 ppm

Gain vs. Temperature TA = T

OFFSET VOLTAGE

Offset Voltage 0.2 1 0.1 0.5 mV

vs. Temperature T
vs. Supply (PSRR) VS = ±5 V to ±15 V 84 100 90 110 dB

INPUT

Common-Mode Rejection Ratio V

Operating Voltage Range Common-Mode ±270 ±270 V

Input Operating Impedance Common-Mode 200 200 kΩ

OUTPUT

Operating Voltage Range R

Output Short Circuit Current ±25 ±25 mA
Capacitive Load Stable Operation 1000 1000 pF

DYNAMIC RESPONSE

Small Signal –3 dB Bandwidth 500 500 kHz
Slew Rate 1.7 2.1 1.7 2.1 V/µs
Full Power Bandwidth V
Settling Time 0.01%, V

OUTPUT NOISE VOLTAGE

0.01 Hz to 10 Hz 15 15 µV p-p
Spectral Density, ≥100 Hz

1

POWER SUPPLY

Operating Voltage Range ±2.5 ± 18 ± 2.5 ±18 V
Quiescent Current V

TEMPERATURE RANGE

For Specified Performance TA = T

NOTES

1

See Figure 19.

Specifications subject to change without notice.

= ±10 V, RL = 2 kΩ

OUT

= 10 kΩ 1 1 3 ppm

R

L

V

S

A

CM

T

A

V

CM

V

CM

MIN

to T

MAX

3 10 3 10 ppm/°C

= ±5 V 1mV
= T

MIN

to T

MAX

620 310µV/°C

= ±250 V dc 77 88 86 96 dB

= T

MIN

to T

MAX

73 82 dB
= 500 V p-p DC to 500 Hz 77 86 dB
= 500 V p-p DC to 1 kHz 88 90 dB

Differential ±13 ± 13 V

Differential 800 800 kΩ

= 10 kΩ±13 ±13 V

L

= 2 kΩ±12.5 ± 12.5 V

R

L

= ±12 V, RL = 2 kΩ±10 ±10 V

V

S

= 20 V p-p 28 28 kHz

OUT

0.1%, V

0.01%, VCM = 10 V Step, V

= 10 V Step 15 15 µs

OUT

= 10 V Step 12 12 µs

OUT

= 0 V 5 5 µs

DIFF

550 550 nV/√Hz

= 0 V 0.9 1 0.9 1 mA

OUT

T

MIN

to T

MIN

MAX

to T

MAX

1.2 1.2 mA

–40 +85 –40 +85 °C

–2–

REV. A

AD629

WARNING!

ESD SENSITIVE DEVICE

ABSOLUTE MAXIMUM RATINGS

Supply Voltage VS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±18 V

Internal Power Dissipation

2

1

DIP (N) . . . . . . . . . . . . . . . . . . . . . . . . See Derating Curves

SOIC (R) . . . . . . . . . . . . . . . . . . . . . . . See Derating Curves

Input Voltage Range, Continuous . . . . . . . . . . . . . . . . ±300 V

Common-Mode and Differential, 10 sec . . . . . . . . . . . ±500 V

Output Short Circuit Duration . . . . . . . . . . . . . . . . Indefinite

Pin 1, Pin 5 . . . . . . . . . . . . . . . . . . –V

– 0.3 V to +VS + 0.3 V

S

Maximum Junction Temperature . . . . . . . . . . . . . . . . . 150°C

Operating Temperature Range . . . . . . . . . . –55°C to +125°C

Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C

Lead Temperature Range (Soldering 60 sec) . . . . . . . . . 300°C

NOTES

1

Stresses above those listed under Absolute Maximum Ratings may cause perma-

nent 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 effect device reliability.

2

Specification is for device in free air: 8-Lead Plastic DIP, θJA = 100°C/W; 8-Lead

SOIC Package, θJA = 155°C/W.

2.0

TJ = 150ⴗC

8-LEAD MINI-DIP PACKAGE

1.5

1.0

8-LEAD SOIC PACKAGE

0.5

MAXIMUM POWER DISSIPATION – Watts

0

–40 –30 –20 –100 102030405060708090

–50

AMBIENT TEMPERATURE – ⴗC

Figure 3. Derating Curve of Maximum Power Dissipation
vs. Temperature for SOIC and PDIP Packages

ORDERING GUIDE

THEORY OF OPERATION

The AD629 is a unity gain differential-to-single-ended amplifier
(Diff Amp) that can reject extremely high common-mode
signals (in excess of 270 V with 15 V supplies). It consists of an
operational amplifier (Op Amp) and a resistor network.

In order to achieve high common-mode voltage range, an internal
resistor divider (Pin 3, Pin 5) attenuates the noninverting signal
by a factor of 20. Other internal resistors (Pin 1, Pin 2, and the
feedback resistor) restores the gain to provide a differential gain
of unity. The complete transfer function equals:

V

= V (+IN ) – V (–IN )

OUT

Laser wafer trimming provides resistor matching so that common­mode signals are rejected while differential input signals are
amplified.

The op amp itself, in order to reduce output drift, uses super
beta transistors in its input stage The input offset current and
its associated temperature coefficient contribute no appreciable
output voltage offset or drift. This has the added benefit of
reducing voltage noise because the corner where 1/f noise becomes
dominant is below 5 Hz. In order to reduce the dependence of
gain accuracy on the op amp, the open-loop voltage gain of the
op amp exceeds 20 million, and the PSRR exceeds 140 dB.

REF(–)

–IN

+IN

–V

21.1k⍀

1

380k⍀

2

380k⍀

3

4

S

380k⍀

20k⍀

AD629

NC = NO CONNECT

NC

8

7

+V

6

OUTPUT

5

REF(+)

S

Figure 4. Functional Block Diagram

Temperature Package Package

Model Range Description Option

AD629AR –40°C to +85°C 8-Lead Plastic SOIC SO-8
AD629AR-REEL
AD629AR-REEL7
AD629BR –40°C to +85°C 8-Lead Plastic SOIC SO-8
AD629BR-REEL
AD629BR-REEL7

1

2

1

2

–40°C to +85°C 8-Lead Plastic SOIC SO-8
–40°C to +85°C 8-Lead Plastic SOIC SO-8

–40°C to +85°C 8-Lead Plastic SOIC SO-8

–40°C to +85°C 8-Lead Plastic SOIC SO-8
AD629AN –40°C to +85°C 8-Lead Plastic DIP N-8
AD629BN –40°C to +85°C 8-Lead Plastic DIP N-8

NOTES

1

13" Tape and Reel of 2500 each

2

7" Tape and Reel of 1000 each

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 the AD629 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. A

–3–

AD629

–Typical Performance Characteristics

(@25ⴗC, VS = ⴞ15 V unless otherwise noted)

100

90

80

70

60

50

40

30

20

COMMON-MODE REJECTION RATIO – dB

10

0

100

1k 10k 100k

FREQUENCY – Hz

1M 10M

Figure 5. Common-Mode Rejection Ratio vs. Frequency

2mV/DIV

VS = ⴞ18V

VS = ⴞ15V

RL = 10k⍀

400

360

320

280

240

200

160

120

80

COMMON-MODE VOLTAGE – ⴞVolts

40

0

020

POWER SUPPLY VOLTAGE – ⴞVolts

TA = +85ⴗC

TA = +25ⴗC

TA = –40ⴗC

18161412108642

Figure 8. Common-Mode Operating Range vs. Power
Supply Voltage

RL = 2k⍀

VS = ⴞ18V

VS = ⴞ15V

VS = ⴞ12V

OUTPUT ERROR – 2mV/DIV

VS = ⴞ10V

–20 –40 4 20

–8–12–16 8 12 16

V

– Volts

OUT

Figure 6. Typical Gain Error Normalized @ V

4V/DIV

= 0 V and

OUT

Output Voltage Operating Range vs. Supply Voltage,
RL = 10 kΩ (Curves Offset for Clarity)

RL = 1k⍀

VS = ⴞ18V

VS = ⴞ15V

VS = ⴞ12V

OUTPUT ERROR – 2mV/DIV

VS = ⴞ10V

–20 –40 4 20

–8–12–16 8 12 16

V

– Volts

OUT

Figure 7. Typical Gain Error Normalized @ V

4V/DIV

OUT

= 0 V

and Output Voltage Operating Range vs. Supply Voltage,

= 1 kΩ (Curves Offset for Clarity)

R

L

VS = ⴞ12V

OUTPUT ERROR – 2mV/DIV

VS = ⴞ10V

–20 –40 4 20

–8–12–16 8 12 16

V

– Volts

OUT

Figure 9. Typical Gain Error Normalized @ V

4V/DIV

= 0 V and

OUT

Output Voltage Operating Range vs. Supply Voltage,

= 2 kΩ (Curves Offset for Clarity)

R

L

VS = ⴞ5V, RL = 10k⍀

VS = ⴞ5V, RL = 2k⍀

= ⴞ5V, RL = 1k⍀

V

S

OUTPUT ERROR – 2mV/DIV

V

= ⴞ2.5V, RL = 1k⍀

S

–5 –10 1 5

–2–3–4234

– Volts

V

OUT

Figure 10. Typical Gain Error Normalized @ V

1V/DIV

OUT

= 0 V
and Output Voltage Operating Range vs. Supply Voltage
(Curves Offset for Clarity)

–4–

REV. A