Analog Devices AD708 b Datasheet

Ultralow Offset Voltage

a

FEATURES
Very High DC Precision

30 mV max Offset Voltage

0.3 mV/8C max Offset Voltage Drift

0.35 mV p-p max Voltage Noise (0.1 Hz to 10 Hz)
5 Million V/V min Open Loop Gain
130 dB min CMRR
120 dB min PSRR

Matching Characteristics

30 mV max Offset Voltage Match

0.3 mV/8C max Offset Voltage Drift Match

130 dB min CMRR Match
Single Version: AD707
Available in 8-Pin Plastic Mini-DIP,

Hermetic Cerdip and TO-99 Metal Can

Packages, Chips and /883B Parts Available.

Dual Op Amp

AD708

CONNECTION DIAGRAMS

TO-99 (H) Package

Plastic (N ), and Cerdip (Q) Packages

PRODUCT DESCRIPTION

The AD708 is a very high precision, dual monolithic operational
amplifier. Each amplifier individually offers excellent dc precision
with the best available max offset voltage and offset voltage drift
of any dual bipolar op amp. In addition, the matching specifica­tions are the best available in any dual op amp.

The AD708 sets a new standards for dual precision op amps by
providing 5 V/µV min open loop gain and guaranteed max input
voltage noise of 350 nV p-p (0.1 Hz to 10 Hz). All dc specifica­tions show excellent stability over temperature, with offset
voltage drift typically 0.1 µV/°C and input bias current drift of
25 pA/°C max. Both CMRR (130 dB min) and PSRR (120 dB
min) are an order of magnitude improved over any available
single monolithic op amp except the AD707.

The AD708 is available in four performance grades. The
AD708J is rated over the commercial temperature range of 0°C
to +70°C and jis available in a plastic mini-DIP package. The
AD708A and AD708B are rated over the industrial temperature
range of –40°C to +85°C and are available in a cerdip and TO­99 package. The AD708S is rated over the military temperature
range of –55°C to +125°C and is available in cerdip and TO-99
packages. Military versions are available processed to MIL­STD-883B, Rev. C.

APPLICATION HIGHLIGHTS

1. The combination of outstanding matching and individual
specifications make the AD708 ideal for constructing high
gain, precision instrumentation amplifiers.

2. The low offset voltage drift and low noise of the AD708
allows the designer to amplify very small signals without
sacrificing overall system performance.

3. The AD708’s 10 V/µV typical open loop gain and 140 dB
common-mode rejection make it ideal for precision
applications.

4. Unmounted dice are available for hybrid circuit applications.

5. The AD708 is an improved replacement for the LT1002.

REV. B

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.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] Fax: [phone]

AD708–SPECIFICATIONS

(@ +258C and 615 V dc, unless otherwise noted)

Model Conditions Min Typ Max Min Typ Max Min Typ Max Units

AD708J/A AD708B AD708S

INPUT OFFSET VOLTAGE

1

to T

T

MIN

MAX

30 100 5 50 5 30 µV

50 150 15 65 15 50 µV
Drift 0.3 1.0 0.1 0.4 0.1 0.3 µV/°C
Long Term Stability 0.3 0.3 0.3 µV/Month

INPUT BIAS CURRENT 1.0 2.5 0.5 1.0 0.5 1 nA

to T

T

MIN

MAX

2.0 4.0 1.0 2.0 1.0 4 nA

Average Drift 15 40 10 25 10 30 pA/°C

OFFSET CURRENT V

= 0 V 0.5 2.0 0.1 1.0 0.1 1 nA

CM

to T

T

MIN

MAX

2.0 4.0 0.2 1.5 0.2 1.5 nA

Average Drift 2 60 1 25 1 25 pA/°C

MATCHING CHARACTERISTICS

2

Offset Voltage 80 50 30 µV

to T

T

MIN

MAX

150 75 50 µV

Offset Voltage Drift 1.0 0.4 0.3 µV/°C
Input Bias Current 4.0 1.0 1.0 nA

to T

T

MIN

MAX

5.0 2.0 2.0 nA

Common-Mode Rejection 120 140 130 140 130 140 dB

to T

T

MIN

MAX

110 130 130 dB

Power Supply Rejection 110 120 120 dB

to T

T

MIN

MAX

110 120 120 dB

Channel Separation 135 140 140 dB

INPUT VOLTAGE NOISE 0.1 Hz to 10 Hz 0.23 0.6 0.23 0.6 0.23 0.35 µV p-p

f = 10 Hz 10.3 18 10.3 12 10.3 12 nV/√
f = 100 Hz 10.0 13.0 10.0 11.0 10.0 11 nV/√

Hz
Hz

f = 1 kHz 9.6 11.0 9.6 11.0 9.6 11 nV/√Hz

INPUT CURRENT NOISE 0.1 Hz to 10 Hz 14 35 14 35 14 35 pA p-p

f = 10 Hz 0.32 0.9 0.32 0.8 0.32 0.8 pA/√
f = 100 Hz 0.14 0.27 0.14 0.23 0.14 0.23 pA/√

Hz
Hz

f = 1 kHz 0.12 0.18 0.12 0.17 0.12 0.17 pA/√Hz

COMMON-MODE

REJECTION RATIO V

OPEN-LOOP GAIN V

= ±13 V 120 140 130 140 130 140 dB

CM

T

to T

MIN

MAX

= ±10 V

O

≥ 2 kΩ 3 10 5 10 4 10 V/µV

R

LOAD

T

to T

MIN

MAX

120 140 130 140 130 140 dB

310 510 47V/µV

POWER SUPPLY

REJECTION RATIO V

= ±3 V to ±18 V 110 130 120 130 120 130 dB

S

T

MIN

to T

MAX

110 130 120 130 120 130 dB

FREQUENCY RESPONSE

Closed Loop Bandwidth 0.5 0.9 0.5 0.9 0.5 0.9 MHz
Slew Rate 0.15 0.3 0.15 0.3 0.15 0.3 V/µs

INPUT RESISTANCE

Differential 60 200 200 MΩ
Common Mode 200 400 400 GΩ

OUTPUT VOLTAGE R

≥ 10 kΩ 13.5 14 13.5 14.0 13.5 14 ±V

LOAD

≥ 2 kΩ 12.5 13.0 12.5 13.0 12.5 13 ±V

R

LOAD

≥ 1 kΩ 12.0 12.5 12.0 12.5 12.0 12.5 ±V

R

LOAD

≥ 2 kΩ

R

LOAD

T

MIN

to T

MAX

12.0 13.0 12.0 13.0 12.0 13 ±V

OPEN-LOOP OUTPUT

RESISTANCE 60 60 60 Ω

–2–

REV. B

AD708

Model Conditions Min Typ Max Min Typ Max Min Typ Max Units

AD708J/A AD708B AD708S

POWER SUPPLY

Quiescent Current 4.5 5.5 4.5 5.5 4.5 5.5 mA
Power Consumption V

= ±15 V

S

No Load 135 165 135 165 135 165 mW

= ±3 V 12 18 12 18 12 18 mW

V

S

Operating Range ±3 ± 18 ± 3 ±18 ±3 ±18 V

NOTES

1

Input offset voltage specifications are guaranteed after 5 minutes of operation at TA = +25°C.

2

Matching is defined as the difference between parameters of the two amplifiers.

All min and max specifications are guaranteed. Specifications in boldface are tested on all production units at final electrical test. Results from those tests are used to
calculate outgoing quality levels.

Specifications subject to change without notice.

ABSOLUTE MAXIMUM RATINGS

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±22 V

Internal Power Dissipation
Input Voltage

3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±V

2

1

S

METALIZATION PHOTOGRAPH

Dimensions shown in inches and (mm).

Contact factory for latest dimensions.

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

Differential Input Voltage . . . . . . . . . . . . . . . . . . +V

and –V

S

S

Storage Temperature Range (Q, H) . . . . . . . –65°C to +150°C

Storage Temperature Range (N) . . . . . . . . . –65°C to +125°C

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

NOTES

1

Stresses above those listed under “Absolute Maximum Ratings” may cause
permanent damage to the device. This is a stress rating only and 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.

2

Thermal Characteristics

8-Pin Plastic Package: θJC = 33°C/Watt, θJA = 100°C/Watt
8-Pin Cerdip package: θJC = 30°C/Watt, θJA = 110°C/Watt
8-Pin Metal Can Package: θJC = 65°C/Watt, θJA = 150°C/Watt.

3

For supply voltages less than ±22 V, the absolute maximum input voltage is
equal to the supply voltage.

REV. B

ORDERING GUIDE

Temperature Package Package

Model Range Description Option*

AD708JN 0°C to +70°C 8-Pin Plastic DIP N-8
AD708AQ –40°C to +85°C 8-Pin Cerdip Q-8
AD708BQ –40°C to +85°C 8-Pin Cerdip Q-8
AD708SQ –55°C to +125°C 8-Pin Cerdip Q-8
AD708AH –40°C to +85°C 8-Pin Header H-08A
AD708BH –40°C to +85°C 8-Pin Header H-08A
AD708SH –55°C to +125°C 8-Pin Header H-08A
AD708SH/883B –55°C to +125°C 8-Pin Header H-08A
AD708J Grade Chips 0°C to +70°C Die
AD708S Grade Chips –55°C to +125°C Die

*N = Plastic DIP; Q = Cerdip; H = Hermetic Metal Can.

–3–