AD706:  Picoampere Input Current Dual Bipolar Op Amp

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_B 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 I_B doubles every 10°C for a 1000x increase at 125°C). The AD706 also achieves the microvolt off-set 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.