Op amp adopts zero-drift, zero-crossover technology

Article By : Texas Instruments

TI's zero-drift technology achieves a low maximum offset voltage of 5μV and a typical offset voltage drift of 0.005μV/°C.

Combining precision and high input linearity into a single device, Texas Instruments (TI) has introduced an op amp that offers both zero-drift and zero-crossover technology. The OPA388 op amp maintains high precision across the entire input range for a variety of industrial applications, including test and measurement, medical and safety equipment, and high-resolution data-acquisition systems, according to the company.

[Texas Instruments OPA388 op amp (cr)]
Figure 1: Texas Instruments’ OPA388 operational amplifier combines precision and high input linearity.

TI's zero-drift technology eliminates temperature drift and flicker noise by delivering a low maximum offset voltage of 5μV, a typical offset voltage drift of 0.005μV/°C and a maximum input bias current of 700pA over the extended industrial temperature range of -40°C to 125°C. Thus, it eliminates the need for costly over-temperature calibration, while increasing DC precision and attaining dynamic error correction.

The device's zero-crossover topology eliminates the input offset transition region of traditional complementary metal-oxide semiconductor (CMOS) op amps, assuring maximum linearity and minimal distortion across the entire common-mode input range.

[Texas Instruments op amp functional diagram (cr)]
Figure 2: Texas Instruments’ OPA388 op amp functional diagram.

With a 10MHz gain bandwidth product (GBW), the OPA388 enables high gain configurations and makes it possible to acquire a wide 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. 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 (BOM) cost.

TI also offers a range of support tools for designers using the OPA388, including a reference design that demonstrates how to use the precision op amp to eliminate crossover nonlinearity in digital-to-analog converters. The reference design uses the DAC8830 precision data converter and REF5050 voltage reference to create an accurate DC calibration system for high-precision applications for wireless infrastructure and test and measurement.

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