Dual Picoampere Input Current Bipolar Op Amp AD706
HIGH DC PRECISION 50 µV max Offset Voltage 0.6 µV/°C max Offset Drift 110 pA max Input Bias Current
Plastic Mini-DIP (N) Cerdip (Q) and Plastic SOIC (R) Packages
LOW NOISE 0.5 µV p Voltage Noise, 0.1 Hz to 10 Hz
LOW POWER 750 µA Supply Current Available in 8-Pin 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
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 IB 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 IB typically only increases by 5× at 125°C (unlike a BiFET amp, for which IB 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.
The AD706 is offered in three varieties of an 8-pin package: plastic mini-DIP, hermetic cerdip and surface mount (SOIC). “J” grade chips are also available. PRODUCT HIGHLIGHTS
1. The AD706 is a dual low drift op amp that offers BiFET level input bias currents, yet has the low IB 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
TYPICAL IB – nA
10 TYPICAL JFET AMP 1
0.1 AD706T 0.01 –55
TEMPERATURE – °C
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