AD8231 Zero Drift Instrumentation Amplifier for Harsh Industrial Environments - Analog Devices

Analog Devices introduce AD8231, a zero-drift, programmable-gain instrumentation amplifier (in-amp), manufactured using Analog Devices'  iCMOS (industrial CMOS) process technology.

 Zero-drift in-amps are often used in harsh industrial environments. The AD8231 zero-drift in-amplifier is designed for industrial sensors, where signals generated by the sensor should be measured precisely in noisy environtment.

AD8231 able to maintain dc precision while adjusting it’s gain values. The new in-amp also offers rail-to-rail inputs and outputs at up to 1-MHz bandwidth. The AD8231 integrate an uncommitted op-amp, which eases system design and reduces cost and board space requirements.

Steve Sockolov, Analog Devices, said:

Zero-drift instrumentation amplifiers can have high noise at high gains for a variety of reasons, including the presence of chopping noise…

…However, the trade-off between offset drift and noise becomes untenable as the gain increases to the level demanded by today’s industrial equipment manufacturers. Analog Devices addressed this challenge using a proprietary auto-zero technique that dramatically lowers the in-amp’s noise profile while eliminating the need for external components, such as switched capacitors..

The AD8231’s key features and spec.:

• Auto-zero amplifiers to maintain a voltage offset of only 50 nV/° C across temperature and over years of operation.
• Internal gain-setting resistors to which limit gain coefficient temperature drift to 10 ppm/° C only.
• Software programmable gains up to 128, programmed through an three-pin interface.
• Operates on a single supply from 3.3 V to 5 V.
• Has rail-to-rail outputs
• High impedance inputs of 10 gigaohms, to avoid performance degradation when using higher impedance sensors.
• Includes an additional on-chip op-amp to extends performance.
• The integrated op-amp provides additional error correction, level shifting, or filtering.
• Ability to eliminate noise-prone discrete components, such as switched capacitors.
• Noise level of 32 nV/rt-Hz,
• 122-dB CMR (common-mode rejection)

Compatibility
The AD8231 is designed to work well with Analog Devices' data converters (including the AD7942, AD7685 and AD7980 PulSAR ADCs), the ADuC702x family of precision analog microcontrollers and ADI's ADR121, ADR43x and ADR44x voltage reference.

In a 16-lead LFCSP package, AD8231 has center paddle, which keeps the part securely soldered to the PCB.

The AD8231 is in sampling now. Production quantities available in April 2007. Priced: $1.69 in 1,000 qty.

More information at: Analog Devices AD8231