If you’re looking for really high precision in a zero-drift op amp, check out the LTC2063 from Linear Tech, err…Analog Devices (ADI recently acquired Linear Tech, so it’ll take a little getting used to). The device draws just 1.3 μA typical (2 μA max) on a 1.8-V supply.
This micropower amplifier offers a maximum input offset voltage of 5 μV at 25°C, and a maximum drift of 0.06 μV/°C from –40°C to +125°C. The maximum input bias current is 15 pA at 25°C, and 100 pA from –40°C to +125°C. Such high precision input characteristics allow the use of large value feedback network resistors, keeping power consumption low without compromising accuracy, even at elevated temperature.
Rail-to-rail inputs and outputs simplify single supply use and enhance dynamic range. An integrated EMI filter provides 114 dB EMI rejection at 1.8 GHz. With low 1/f noise inherent to its zero-drift architecture, the LTC2063 is suited for amplifying and conditioning low-frequency sensor signals in high-temperature industrial and automotive systems, as well as portable and wireless sensor network applications.
The part is available in SOT-23 and SC70 packages. The SC70 version includes a shutdown mode which reduces current consumption to just 90 nA when the amplifier is not in use. Pricing starts at $1.50 each in 1000-piece quantities.