Analog Devices AD704 Datasheet

a

32120 19

18

17
16
15
14

9

10

11

12

13

4

5

6
7
8

+IN4

NC
–V

S

NC
+IN3

–IN1

OUT1NCOUT4

–IN4

+IN1

NC

+V

S

NC

+IN2

–IN2

OUT2NCOUT3

–IN3

AMP 1

AMP 2

AMP 4

AMP 3

NC = NO CONNECT

AD704

Quad Picoampere Input Current

Bipolar Op Amp

AD704

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

B

OUTPUT

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

OUTPUT

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-

B

beta bipolar input transistors to achieve picoampere input bias
current levels (similar to FET input amplifiers at room tempera­ture), while its I
(unlike a BiFET amp, for which I

typically only increases by 5× at +125°C

B

doubles every 10°C resulting

B

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.

CONNECTION DIAGRAMS

14-Pin Plastic DIP (N)

14-Pin Cerdip (Q) Packages

1

–IN

2

1 4

+

3

IN

+V

+

IN

–IN

AD704

S

4

(TOP VIEW)

5

6

2

7

14

OUTPUT

13

–IN

+

12

IN

–V

11

S

+

10

IN

–IN

9

3

8

OUTPUT

(E) Package

16-Pin SOIC

(R) Package

OUTPUT

1

–IN

2

14

+

IN

3

4

S

5

6

7

8

NC = NO CONNECT

AD704

(TOP VIEW)

2

3

+V

+

IN

–IN

OUTPUT

NC NC

20-Terminal LCC

16

OUTPUT

15

–IN

+

14

IN

13

–V

+

12

IN

11

–IN

10

OUTPUT

9

S

100

Since it has only 1/20 the input bias current of an AD OP07, the
AD704 does not require the commonly used “balancing”

10

B

1

TYPICAL I – nA

0.1

TYPICAL JFET AMP

AD704T

0.01
–55 +25 +125

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.

TEMPERATURE – °C

Figure 1. Input Bias Current Over Temperature

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.

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

AD704–SPECIFICATIONS

(@ TA = +258C, VCM = 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–TMAX

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

T

MIN–TMAX

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

S

VS = ±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

1

VCM = 0 V 100 270 80 150 80 200 pA

= ±13.5 V 300 200 250 pA

V

CM

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

T

MIN–TMAX

T

MIN–TMAX

INPUT OFFSET CURRENT V

VCM = 0 V 300 200 600 pA
VCM = ±13.5 V 400 300 700 pA

= 0 V 80 250 30 100 50 150 pA

CM

= ±13.5 V 300 150 200 pA

V

CM

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

T

MIN–TMAX

T

MIN–TMAX

VCM = 0 V 100 300 80 200 80 400 pA
VCM = ±13.5 V 100 400 80 300 100 500 pA

MATCHING CHARACTERISTICS

Offset Voltage 250 130 150 µV

Input Bias Current

2

Common-Mode Rejection

Power Supply Rejection

Crosstalk

5

4

T

MIN–TMAX

T

3

MIN–TMAX

T

MIN–TMAX

94 110 104 dB
94 104 104 dB
94 110 110 dB

T

MIN–TMAX

94 106 106 dB
f = 10 Hz
R

= 2 kΩ 150 150 150 dB

LOAD

400 200 250 µV
500 300 400 pA
600 400 600 pA

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–TMAX

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

CM

T

MIN–TMAX

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

O

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

R

LOAD

T

MIN–TMAX

= ±10 V

V

O

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

R

LOAD

T

MIN–TMAX

150 1500 300 1500 300 1500 V/mV

150 1000 200 1000 100 1000 V/mV

–2–

REV. A

Model AD704J/A AD704K/B AD704T

Conditions Min Typ Max Min Typ Max Min Typ Max Units

OUTPUT CHARACTERISTICS

Voltage Swing R

= 10 kΩ

LOAD

T

MIN–TMAX

±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

T

MIN–TMAX

1.6 2.6 1.6 2.6 1.6 2.6 mA

TRANSISTOR COUNT # of Transistors 180 180 180

NOTES

1

Bias current specifications are guaranteed maximum at either input.

2

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

3

CMRR match is the difference of ∆VOS/∆VCM between any two amplifiers, expressed in dB.

4

PSRR match is the difference between ∆VOS/∆V

5

See Figure 2a for test circuit.

for any two amplifiers, expressed in dB.

SUPPLY

All min and max specifications are guaranteed.
Specifications subject to change without notice.

ABSOLUTE MAXIMUM RATINGS

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

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

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

Differential Input Voltage

3

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

1

METALIZATION PHOTOGRAPH

Dimensions shown in inches and (mm).

Contact factory for latest dimensions.

S

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

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

Specification is for device in free air:
14-Pin Plastic Package: θJA = 150°C/Watt
14-Pin Cerdip Package: θJA = 110°C/Watt
16-Pin SOIC Package: θJA = 100°C/Watt
20-Terminal LCC Package: θJA = 150°C/Watt

3

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.

Ω

9k

Ω

1k

1/4

INPUT

*

SIGNAL

1k

ALL 4 AMPLIFIERS ARE CONNECTED AS SHOWN

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

Ω

OUTPUT

Ω

2.5k

COM

+V

–V

S

0.1 µF

0.1 µF

S

1µF

1µF

AD704
PIN 4

AD704
PIN 11

–80

AMP4

–100

AMP2

–120

CROSSTALK – dB

–140

–160

10 100 1k 10k

FREQUENCY – Hz

AMP3

100k

Figure 2b. Crosstalk vs. Frequency

AD704

REV. A

Figure 2a. Crosstalk Test Circuit

–3–