Analog Devices AD706KN, AD706JR-REEL, AD706JR, AD706JN, AD706AR-REEL Datasheet

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Dual Picoampere Input

FEATURE HIGH DC PRECISION

50 mV max Offset Voltage

0.6 mV/8C max Offset Drift 110 pA max Input Bias Current

LOW NOISE

0.5 mV p-p Voltage Noise, 0.1 Hz to 10 Hz LOW POWER

750 mA Supply Current Available in 8-Lead Plastic Mini-DlP, Hermetic Cerdip

and Surface Mount (SOIC) Packages

Available in Tape and Reel in Accordance with

EIA-481A Standard

Single Version: AD705, Quad Version: AD704 PRIMARY APPLICATIONS

Low Frequency Active Filters Precision Instrumentation Precision Integrators

Current Bipolar Op Amp

AD706

CONNECTION DIAGRAM

Plastic Mini-DIP (N)

Cerdip (Q) and

Plastic SOIC (R) Packages

AMPLIFIER 1 AMPLIFIER 2

AD706

TOP VIEW

V1 OUTPUT –IN

1INV–

–IN

1IN

OUTPUT

The AD706 is offered in three varieties of an 8-lead package: plastic mini-DIP, hermetic cerdip and surface mount (SOIC). “J” grade chips are also available.

PRODUCT DESCRIPTION

The AD706 is a dual, 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 superbeta

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

typically only increases by 5× at 125°C (unlike

doubles every 10°C for a 1000×

increase at 125°C). The AD706 also achieves the microvolt offset voltage and low noise characteristics of a precision bipolar input amplifier.

Since it has only 1/20 the input bias current of an OP07, the AD706 does not require the commonly used “balancing” resistor. Furthermore, the current noise is 1/5 that of the OP07, which makes this amplifier usable with much higher source impedances. At 1/6 the supply current (per amplifier) of the OP07, the AD706 is better suited for today’s higher density boards.

The AD706 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 AD706 is internally compensated for unity gain and is available in five performance grades. The AD706J and AD706K are rated over the commercial temperature range of 0°C to +70°C. The AD706A and AD706B are rated over the industrial temperature range of –40°C to +85°C.

PRODUCT HIGHLIGHTS

1. The AD706 is a dual low drift op amp that offers BiFET level input bias currents, yet has the low I

drift of a bipolar

amplifier. It may be used in circuits using dual op amps such as the LT1024.

2. The AD706 provides both low drift and high dc precision.

3. The AD706 can be used in applications where a chopper amplifier would normally be required but without the chopper’s inherent noise.

100

– nA

TYPICAL I

0.1

0.01 –55 +125+25 +110

TYPICAL JFET AMP

AD706

TEMPERATURE – 8C

Figure 1. Input Bias Current vs. Temperature

REV. C

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: 781/329-4700 World Wide Web Site: http://www.analog.com Fax: 781/326-8703 © Analog Devices, Inc., 1997

AD706–SPECIFICA TIONS

(@ TA = +258C, VCM = 0 V and 615 V dc, unless otherwise noted)

AD706J/A AD706K/B

Parameter Conditions Min Typ Max Min Typ Max Units

INPUT OFFSET VOLTAGE

Initial Offset 30 100 10 50 µV Offset T

MIN

to T

MAX

40 150 25 100 µV vs. Temp, Average TC 0.2 1.5 0.2 0.6 µV/°C vs. Supply (PSRR) VS = ±2 V to ±18 V 110 132 112 132 dB

MIN

to T

MAX

VS = ±2.5 V to ±18 V 106 126 108 126 dB

Long Term Stability 0.3 0.3 µV/Month

INPUT BIAS CURRENT

VCM = 0 V 50 200 30 110 pA

VCM = ±13.5 V 250 160 pA vs. Temp, Average TC 0.3 0.2 pA/°C T

to T

MIN MIN

to T

MAX MAX

VCM = 0 V 300 200 pA

VCM = ±13.5 V 400 300 pA

INPUT OFFSET CURRENT VCM = 0 V 30 150 30 100 pA

VCM = ±13.5 V 250 200 pA vs. Temp, Average TC 0.6 0.4 pA/°C T

to T

MIN MIN

to T

MAX MAX

VCM = 0 V 80 250 80 200 pA

VCM = ±13.5 V 80 350 80 300 pA

MATCHING CHARACTERISTICS

Offset Voltage 150 75 µV

Input Bias Current

to T

MIN

to T

MAX

250 150 µV 300 150 pA 500 250 pA

Common-Mode Rejection 106 110 dB

MIN

to T

MAX

106 108 dB

Power Supply Rejection 106 110 dB

MIN

to T

MAX

104 106 dB

Crosstalk @ f = 10 Hz

(Figure 19a) RL = 2 kΩ 150 150 dB

FREQUENCY RESPONSE

Unity Gain Crossover

Frequency 0.8 0.8 MHz

Slew Rate G = –1 0.15 0.15 V/µs

MIN

to T

MAX

0.15 0.15 V/µs

INPUT IMPEDANCE

Differential 40i2 40i2MΩipF Common Mode 300i2 300i2GΩipF

INPUT VOLTAGE RANGE

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

Ratio VCM = ±13.5 V 110 132 114 132 dB

MIN

to T

MAX

108 128 108 128 dB

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

f = 10 Hz 50 50 fA/√Hz

INPUT VOLTAGE NOISE 0.1 Hz to 10 Hz 0.5 0.5 1.0 µV p-p

f = 10 Hz 17 17 nV/√Hz

f = 1 kHz 15 22 15 22 nV/√Hz

OPEN-LOOP GAIN VO = ± 12 V

= 10 kΩ 200 2000 400 2000 V/mV

LOAD

MIN

to T

MAX

150 1500 300 1500 V/mV VO = ±10 V R

2 kΩ 200 1000 300 1000 V/mV

LOAD =

MIN

to T

MAX

150 1000 200 1000 V/mV

OUTPUT CHARACTERISTICS

Voltage Swing R

= 10 kΩ±13 ±14 ±13 ±14 V

LOAD

MIN

to T

MAX

±13 ±14 ±13 ±14 V

Current Short Circuit ± 15 ±15 mA Capacitive Load

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

–2–

REV. C

AD706

WARNING!

ESD SENSITIVE DEVICE

Parameter Conditions Min Typ Max Min Typ Max Units

AD706J/A AD706K/B

POWER SUPPLY

Rated Performance ± 15 ± 15 V Operating Range ± 2.0 ±18 ± 2.0 ±18 V Quiescent Current, Total 0.75 1.2 0.75 1.2 mA

MIN

to T

MAX

0.8 1.4 0.8 1.4 mA

TRANSISTOR COUNT # of Transistors 90 90

NOTES

Bias current specifications are guaranteed maximum at either input.

Input bias current match is the difference between corresponding inputs (IB of –IN of Amplifier #1 minus IB of –IN of Amplifier #2).

CMRR match is the difference between

PSRR match is the difference between

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

ABSOLUTE MAXIMUM RATINGS

∆VOS#1

∆V

∆VOS#1

∆V

SUPPLY

for amplifier #1 and

for amplifier #l and

Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±18 V Internal Power Dissipation

(Total: Both Amplifiers)

. . . . . . . . . . . . . . . . . . . . 650 mW Input Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±V Differential Input Voltage3 . . . . . . . . . . . . . . . . . . . . +0.7 Volts Output Short Circuit Duration . . . . . . . . . . . . . . . . Indefinite Storage Temperature Range (Q) . . . . . . . . . –65°C to +150°C Storage Temperature Range (N, R) . . . . . . . –65°C to +125°C Operating Temperature Range

AD706J/K . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to +70°C AD706A/B . . . . . . . . . . . . . . . . . . . . . . . . . –40°C to +85°C

Lead Temperature (Soldering 10 secs) . . . . . . . . . . . . +300°C

NOTES

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 affect device reliability.

Specification is for device in free air:

8-Lead Plastic Package: θJA = 100°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.

8-Lead Cerdip Package: θJA = 110°C/Watt 8-Lead Small Outline Package: θJA = 155°C/Watt

∆VOS#2

∆V

∆VOS#2

∆V

SUPPLY

for amplifier #2 expressed in dB.

ORDERING GUIDE

Temperature Package

Model Range Description Option*

AD706AN –40°C to +85°C Plastic DIP N-8 AD706JN 0°C to +70°C Plastic DIP N-8 AD706KN 0°C to +70°C Plastic DIP N-8 AD706JR 0°C to +70°C SOIC R-8 AD706JR-REEL 0°C to +70°C Tape and Reel AD706AQ –40°C to +85°C Cerdip Q-8 AD706BQ –40°C to +85°C Cerdip Q-8 AD706AR –40°C to +85°C SOIC R-8 AD706AR-REEL – 40°C to +85°C Tape and Reel

*N = Plastic DIP; Q = Cerdip, R = Small Outline Package.

METALIZATION PHOTOGRAPH

Dimensions shown in inches and (mm).

Contact factory for latest dimensions.

OUTPUT A

–INPUT A

+INPUT A

–V

0.074 (1.88)

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 AD706 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. C

–3–

0.118 (3.00)

6 5

OUTPUT B

–INPUT B +INPUT B

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