Dual Picoampere Input Current Bipolar Op Amp AD706 FEATURES CONNECTION DIAGRAM High DC Precision 100 V Max Offset Voltage Plastic Mini-DIP (N) and 1.5 V/ C Max Offset Drift Plastic SOIC (R) Packages 200 pA Max Input Bias Current 0.5 V p-p Voltage Noise, 0.1 Hz to 10 Hz AMPLIFIER 1 AMPLIFIER 2 750 A Supply Current AD706 OUTPUT 1 8 V Available in 8-Lead Plastic Mini-DlP and Surface-Mount (SOIC) Packages IN 2 7 OUTPUT Available in Tape and Reel in Accordance with IN IN 3 6 EIA-481A Standard V IN 4 5 Quad Version: AD704 TOP VIEW APPLICATIONS Low Frequency Active Filters Precision Instrumentation Precision Integrators GENERAL DESCRIPTION PRODUCT HIGHLIGHTS The AD706 is a dual, low power, bipolar op amp that has the 1. The AD706 is a dual low drift op amp that offers JFET low input bias current of a JFET amplifier, but which offers a level input bias currents, yet has the low I drift of a bipolar B significantly lower I drift over temperature. It utilizes superbeta amplifier. It may be used in circuits using dual op amps B bipolar input transistors to achieve picoampere input bias current such as the LT1024. levels (similar to FET input amplifiers at room temperature), 2. The AD706 provides both low drift and high dc precision. while its I typically only increases by 5 at 125C (unlike a B 3. The AD706 can be used in applications where a chopper JFET amp, for which I doubles every 10C for a 1000 B amplifier would normally be required but without the increase at 125C). The AD706 also achieves the microvolt choppers inherent noise. offset voltage and low noise characteristics of a precision bipolar input amplifier. Since it has < 200 pA of bias current, the AD706 does not 100 require the commonly used balancing resistor. Furthermore, the current noise is only 50 fA/Hz, which makes this amplifier usable with very high source impedances. At 600 A max supply 10 current (per amplifier), the AD706 is well suited for todays high density boards. TYPICAL JFET AMP The AD706 is an excellent choice for use in low frequency 1 active filters in 12-bit 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 0.1 in five performance grades. The AD706J is rated over the commercial temperature range of 0C to +70C. The AD706A is AD706 rated for the extended industrial temperature range of 40C to +85C. 0.01 55 +25 +110 +125 TEMPERATURE C The AD706 is offered in two varieties of an 8-lead package: plastic mini-DIP and surface-mount (SOIC). Figure 1. Input Bias Current vs. Temperature REV. E 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 that One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. may result from its use. No license is granted by implication or otherwise Tel: 781/329-4700 www.analog.com under any patent or patent rights of Analog Devices. Trademarks and Fax: 781/326-8703 2003 Analog Devices, Inc. All rights reserved. registered trademarks are the property of their respective owners. TYPICAL I nA B( T = +25 C, V = 0 V and 15 V dc, unless otherwise noted.) A CM AD706SPECIFICATIONS AD706J/A Parameter Conditions Min Typ Max Unit INPUT OFFSET VOLTAGE Initial Offset 30 100 V Offset T to T 40 150 V MIN MAX vs. Temperature, Average TC 0.2 1.5 V/C vs. Supply (PSRR) V = 2 V to 18 V 110 132 dB S T to T V = 2.5 V to 18 V 106 126 dB MIN MAX S Long Term Stability 0.3 V/Month 1 INPUT BIAS CURRENT V = 0 V 50 200 pA CM V = 13.5 V 250 pA CM vs. Temperature, Average TC 0.3 pA/C T to T V = 0 V 300 pA MIN MAX CM T to T V = 13.5 V 400 pA MIN MAX CM INPUT OFFSET CURRENT V = 0 V 30 150 pA CM V = 13.5 V 250 pA CM vs. Temperature, Average TC 0.6 pA/C T to T V = 0 V 80 250 pA MIN MAX CM T to T V = 13.5 V 80 350 pA MIN MAX CM MATCHING CHARACTERISTICS Offset Voltage 150 V T to T 250 V MIN MAX 2 Input Bias Current 300 pA T to T 500 pA MIN MAX Common-Mode Rejection 106 dB T to T 106 dB MIN MAX Power Supply Rejection 106 dB T to T 104 dB MIN MAX Crosstalk (Figure 2a) f = 10 Hz R = 2 k 150 dB L FREQUENCY RESPONSE Unity Gain Crossover Frequency 0.8 MHz Slew Rate G = 1 0.15 V/s T to T 0.15 V/s MIN MAX INPUT IMPEDANCE Differential 40 2 M pF Common Mode 300 2 G pF INPUT VOLTAGE RANGE Common-Mode Voltage 13.5 14 V Common-Mode Rejection Ratio V = 13.5 V 110 132 dB CM T to T 108 128 dB MIN MAX INPUT CURRENT NOISE 0.1 Hz to 10 Hz 3 pA p-p f = 10 Hz 50 fA/Hz INPUT VOLTAGE NOISE 0.1 Hz to 10 Hz 0.5 V p-p f = 10 Hz 17 nV/Hz f = 1 kHz 15 22 nV/Hz OPEN-LOOP GAIN V = 12 V O R = 10 k 200 2000 V/mV LOAD T to T 150 1500 V/mV MIN MAX V = 10 V O R = 2 k 200 1000 V/mV LOAD T to T 150 1000 V/mV MIN MAX OUTPUT CHARACTERISTICS Voltage Swing R = 10 k 13 14 V LOAD T to T 13 14 V MIN MAX Current Short Circuit 15 mA Capacitive Load Drive Capability Gain = +1 10,000 pF 2 REV. E