Zero-crossover operational amplifier achieves zero-drift
Claimed to be the first operational amplifier (op amp) to offer both zero-drift and zero-crossover technology, the OPA388 maintains high precision across the entire input range for industrial applications, including test and measurement, medical and safety equipment, and high-resolution data-acquisition systems.
The zero-drift technology eliminates temperature drift and flicker noise to attain the highest DC precision and dynamic error correction, says the company. It claims that it eliminates the input offset transition region of traditional CMOS op amps, assuring maximum linearity and minimal distortion across the entire common-mode input range. It continues to say that the zero-crossover topology eliminates offset errors caused by common-mode limitations to achieve linear output and true rail-to-rail input operation, for DC precision. It delivers a low maximum offset voltage of 5microV, a typical offset voltage drift of 0.005microV/degree C and a maximum input bias current of 700pA over the extended industrial temperature range of -40 to +125°C. This eliminates the need for costly over-temperature calibration and increases DC precision, claims the company.
With a 10MHz gain bandwidth product, the OPA388 enables high gain configurations and makes it possible to acquire a range of signal types and frequencies to support equipment from precision weigh scales to heart rate monitors.
The low total harmonic distortion of -132dBc and voltage noise of 7nV/√Hz help produce a high-resolution signal chain for specialised applications such as programmable logic controllers, precision field transmitters and motion-control equipment.
Finally, merging zero-drift and zero-crossover technology reduces signal-chain complexity and external component count, allowing designers to minimise board space and bill of materials cost.
The OPA388 is available in a 4.9 x 3.9mm SOIC. A reference design is available to demonstrate how to use the op amp to eliminate crossover non-linearity in DACs.