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.

AD704

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 617/329-4700 Fax: 617/326-8703

FEATURES

High DC Precision

75 mV max Offset Voltage

1 mV/8C max Offset Voltage Drift

150 pA max Input Bias Current

0.2 pA/8C typical I

Drift

Low Noise

0.5 mV p-p typical Noise, 0.1 Hz to 10 Hz

Low Power

600 mA max Supply Current per Amplifier

Chips & MIL-STD-883B Processing Available

Available in Tape and Reel in Accordance

with EIA-481A Standard

Single Version: AD705, Dual Version: AD706

PRIMARY APPLICATIONS

Industrial/Process Controls

Weigh Scales

ECG/EKG Instrumentation

Low Frequency Active Filters

PRODUCT DESCRIPTION

The AD704 is a quad, low power bipolar op amp that has the

low input bias current of a BiFET amplifier but which offers a

significantly lower I

drift over temperature. It utilizes Super-

beta bipolar input transistors to achieve picoampere input bias

current levels (similar to FET input amplifiers at room tempera-

ture), while its I

typically only increases by 5× at +125°C

(unlike a BiFET amp, for which I

doubles every 10°C resulting

in a 1000× increase at +125°C). Furthermore the AD704

achieves 75 µV offset voltage and low noise characteristics of a

precision bipolar input op amp.

100

0.1

0.01

–55 +25 +125

TEMPERATURE – °C

TYPICAL I – nA

TYPICAL JFET AMP

AD704T

Figure 1. Input Bias Current Over Temperature

CONNECTION DIAGRAMS

Quad Picoampere Input Current

Bipolar Op Amp

14-Pin Plastic DIP (N)

14-Pin Cerdip (Q) Packages

1 4

OUTPUT

–IN

OUTPUT

–IN

OUTPUT

AD704

(TOP VIEW)

–V

16-Pin SOIC

(R) Package

OUTPUT

–IN

OUTPUT

–IN

OUTPUT

–V

AD704

(TOP VIEW)

NC = NO CONNECT

NC NC

20-Terminal LCC

(E) Package

20 19

+IN4

–V

+IN3

–IN1

OUT1

OUT4

–IN4

+IN1

+IN2

–IN2

OUT2

OUT3

–IN3

AMP 1

AMP 2

AMP 4

AMP 3

NC = NO CONNECT

AD704

Since it has only 1/20 the input bias current of an AD OP07, the

AD704 does not require the commonly used “balancing”

resistor. Furthermore, the current noise is 1/5 that of the

AD OP07 which makes the AD704 usable with much higher

source impedances. At 1/6 the supply current (per amplifier) of

the AD OP07, the AD704 is better suited for today’s higher

density circuit boards and battery powered applications.

The AD704 is an excellent choice for use in low frequency

active filters in 12- and 14-bit data acquisition systems, in

precision instrumentation, and as a high quality integrator. The

AD704 is internally compensated for unity gain and is available

in five performance grades. The AD704J and AD704K are rated

over the commercial temperature range of 0°C to +70°C. The

AD704A and AD704B are rated over the industrial temperature

of –40°C to +85°C. The AD704T is rated over the military

temperature range of –55°C to +125°C and is available

processed to MIL-STD-883B, Rev. C.

REV. A

–2–

AD704–SPECIFICATIONS

(@ T

= +258C, V

= 0 V, and 615 V dc, unless otherwise noted)

Model AD704J/A AD704K/B AD704T

Conditions Min Typ Max Min Typ Max Min Typ Max Units

INPUT OFFSET VOLTAGE

Initial Offset 50 150 30 75 30 100 µV

Offset T

MIN

–T

MAX

100 250 50 150 80 150 µV

vs. Temp, Average TC 0.2 1.5 0.2 1.0 1.0 µV/°C

vs. Supply (PSRR) V

= ±2 to ±18 V 100 132 112 132 112 132 dB

MIN

–T

MAX

= ±2.5 to ±18 V 100 126 108 126 108 126 dB

Long Term Stability 0.3 0.3 0.3 µV/month

INPUT BIAS CURRENT

= 0 V 100 270 80 150 80 200 pA

= ±13.5 V 300 200 250 pA

vs. Temp, Average TC 0.3 0.2 1.0 pA/°C

MIN

–T

MAX

= 0 V 300 200 600 pA

MIN

–T

MAX

= ±13.5 V 400 300 700 pA

INPUT OFFSET CURRENT V

= 0 V 80 250 30 100 50 150 pA

= ±13.5 V 300 150 200 pA

vs. Temp, Average TC 0.6 0.4 0.4 pA/°C

MIN

–T

MAX

= 0 V 100 300 80 200 80 400 pA

MIN

–T

MAX

= ±13.5 V 100 400 80 300 100 500 pA

MATCHING CHARACTERISTICS

Offset Voltage 250 130 150 µV

MIN

–T

MAX

400 200 250 µV

Input Bias Current

500 300 400 pA

MIN

–T

MAX

600 400 600 pA

Common-Mode Rejection

94 110 104 dB

MIN

–T

MAX

94 104 104 dB

Power Supply Rejection

94 110 110 dB

MIN

–T

MAX

94 106 106 dB

Crosstalk

f = 10 Hz

LOAD

= 2 kΩ 150 150 150 dB

FREQUENCY RESPONSE

UNITY GAIN

Crossover Frequency 0.8 0.8 0.8 MHz

Slew Rate, Unity Gain G = –1 0.15 0.15 0.15 V/µs

Slew Rate T

MIN

–T

MAX

0.1 0.1 0.1 V/µs

INPUT IMPEDANCE

Differential 40i240i240i2MΩipF

Common-Mode 300i2 300i2 300i2GΩipF

INPUT VOLTAGE RANGE

Common-Mode Voltage ±13.5 ±14 ±13.5 ±14 ±13.5 ±14 V

Common-Mode Rejection Ratio V

= ±13.5 V 100 132 114 132 110 132 dB

MIN

–T

MAX

98 128 108 128 108 128 dB

INPUT CURRENT NOISE 0.1 to 10 Hz 3 3 3 pA p-p

f = 10 Hz 50 50 50 fA/√Hz

INPUT VOLTAGE NOISE 0.1 to 10 Hz 0.5 0.5 2.0 0.5 2.0 µV p-p

f = 10 Hz 17 17 17 nV/√Hz

f = 1 kHz 15 22 15 22 15 22 nV/√Hz

OPEN-LOOP GAIN V

= ±12 V

LOAD

= 10 kΩ 200 2000 400 2000 400 2000 V/mV

MIN

–T

MAX

150 1500 300 1500 300 1500 V/mV

= ±10 V

LOAD

= 2 kΩ 200 1000 300 1000 200 1000 V/mV

MIN

–T

MAX

150 1000 200 1000 100 1000 V/mV

METALIZATION PHOTOGRAPH

Dimensions shown in inches and (mm).

Contact factory for latest dimensions.

–80

–100

–120

–140

–160

10 100 1k 10k

100k

FREQUENCY – Hz

CROSSTALK – dB

AMP4

AMP2

AMP3

Figure 2b. Crosstalk vs. Frequency

AD704

Model AD704J/A AD704K/B AD704T

Conditions Min Typ Max Min Typ Max Min Typ Max Units

OUTPUT CHARACTERISTICS

Voltage Swing R

LOAD

= 10 kΩ

MIN

–T

MAX

±13 ±14 ±

13 ±14 ±13 ±14 V

Current Short Circuit ±15 ±15 ±15 mA

CAPACITIVE LOAD

Drive Capability Gain = + 1 10,000 10,000 10,000 pF

POWER SUPPLY

Rated Performance ±15 ±15 ±15 V

Operating Range ±2.0 ±18 ±2.0 ±18 ±2.0 ±18 V

Quiescent Current 1.5 2.4 1.5 2.4 1.5 2.4 mA

MIN

–T

MAX

1.6 2.6 1.6 2.6 1.6 2.6 mA

TRANSISTOR COUNT # of Transistors 180 180 180

NOTES

Bias current specifications are guaranteed maximum at either input.

Input bias current match is the maximum difference between corresponding inputs of all four amplifiers.

CMRR match is the difference of ∆V

/∆V

between any two amplifiers, expressed in dB.

PSRR match is the difference between ∆V

/∆V

SUPPLY

for any two amplifiers, expressed in dB.

See Figure 2a for test circuit.

All min and max specifications are guaranteed.

Specifications subject to change without notice.

REV. A

–3–

ABSOLUTE MAXIMUM RATINGS

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

Internal Power Dissipation (+25°C) . . . . . . . . . . . See Note 2

Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±V

Differential Input Voltage

. . . . . . . . . . . . . . . . . . . . . . . ±0.7 V

Output Short Circuit Duration (Single Input) . . . . . Indefinite

Storage Temperature Range

(Q) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to +150°C

(N, R) . . . . . . . . . . . . . . . . . . . . . . . . . . . –65°C to +125°C

Operating Temperature Range

AD704J/K . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C

AD704A/B . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C

AD704T . . . . . . . . . . . . . . . . . . . . . . . . . . –55°C to +125°C

Lead Temperature Range (Soldering 10 seconds) . . . . +300°C

NOTES

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.

Specification is for device in free air:

14-Pin Plastic Package: θ

= 150°C/Watt

14-Pin Cerdip Package: θ

= 110°C/Watt

16-Pin SOIC Package: θ

= 100°C/Watt

20-Terminal LCC Package: θ

= 150°C/Watt

The input pins of this amplifier are protected by back-to-back diodes. If the

differential voltage exceeds ±0.7 volts, external series protection resistors should

be added to limit the input current to less than 25 mA.

–V

1/4

AD704

ALL 4 AMPLIFIERS ARE CONNECTED AS SHOWN

OUTPUT

THE SIGNAL INPUT (SUCH THAT THE AMPLIFIER'S OUTPUT IS AT MAX

AMPLITUDE WITHOUT CLIPPING OR SLEW LIMITING) IS APPLIED TO ONE

AMPLIFIER AT A TIME. THE OUTPUTS OF THE OTHER THREE AMPLIFIERS ARE

THEN MEASURED FOR CROSSTALK.

AD704

PIN 4

AD704

PIN 11

COM

0.1 µF

1µF

0.1 µF

1µF

INPUT

SIGNAL

Ω

2.5k

Ω

Figure 2a. Crosstalk Test Circuit

Part #	AD704KN
Description	IC OPAMP GP 4 CIRCUIT 14DIP
Category	IC
Availability	In Stock
Qty	1

AD704KN

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