The AD706 is a dual, low power, bipolar op amp that has the low input bias current of a JFET 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 5μA at 125°C (unlike a JFET amp, for which IB doubles every 10°C for a 1000μA 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 < 200 pA of bias current, the AD706 does not 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 600μA max supply current (per amplifier), the AD706 is well suited for today’s high density boards.
The AD706 is a dual, low power, bipolar op amp that combines the low input bias current of a JFET amplifier with significantly lower input bias current drift over temperature. It utilizes superbeta bipolar input transistors to achieve picoampere-level input bias currents and offers microvolt offset voltage and low noise characteristics suitable for precision instrumentation.
The device is available in two performance grades: the AD706J rated for commercial temperatures (0 °C to +70 °C) and the AD706A for extended industrial temperatures (-40 °C to +85 °C). It comes in 8-lead PDIP and SOIC packages. Key features include a maximum offset voltage of 1.5 µV, input bias current as low as 200 pA, and suitability for high source impedance applications without the need for balancing resistors.
| Max Offset Voltage | 1.5 µV |
|---|---|
| Max Offset Drift | 200 pA |
| Max Input Bias Current | 0.5 p-p Voltage Noise, 0.1 Hz to 10 Hz 750 /H9262A |
| Supply Current (Max) | 600 µA |
| Operating Temperature Range AD706J | 0 °C to +70 °C |
| Operating Temperature Range AD706A | -40 °C to +85 °C |
The device is offered in an 8-lead PDIP and surface-mount (SOIC) package.
No, because it has less than 200 pA of bias current, it does not require commonly used balancing resistors.