That's the case demonstrated by the OPAx388 precision operating amplifier (op amp) family from Texas Instruments, Figure 1. This series offers high precision across the entire input range for a variety of industrial applications, including high-end test and measurement; load cells/weight scales; medical and safety equipment; and high-resolution data-acquisition systems. It's available in single-channel (OPA388), dual-channel (OPA2388), and quad-channel (OPA4388) versions, with only minor differences in critical specifications.
The op amps in this family implements TI's proprietary zero-drift technology, which eliminates temperature drift and flicker noise to yield the highest DC precision and dynamic error correction. In addition, its zero-crossover topology eliminates offset errors caused by common-mode limitations of traditional CMOS op amps, yielding a highly linear output and true rail-to-rail input operation.
The numbers tell the story, as the OPA388 has a maximum offset voltage of just 5 µV, a typical offset voltage drift of 0.005 μV/°C and a maximum input bias current of 700 pA over the extended industrial temperature range of -40° C to 125° C. This eliminates the need for costly, complex calibration over the temperature range and increases DC precision.
In many cases, high-precision amplifiers have limited gain bandwidth (GBW) product, but the 10-MHz rating of the OPA388 supports high-gain configurations and makes it a good fit for applications spanning precision weight scales to heart-rate monitors, Figure 2. The ultra-low total harmonic distortion of -132 dBc and voltage noise of 7 nV/√Hz are commensurate with the front-end demands of a high-resolution signal chain.
Texas Instruments also offers a reference design that demonstrates how to use the precision op amp to eliminate crossover nonlinearity in digital-to-analog converters, Figure 3. This design uses their DAC8830 precision data converter and REF5050 voltage reference to create an accurate DC-calibration system for high-precision applications such as wireless infrastructure as well as test-and-measurement installations.
The single-channel OPA388 is available in the VSSOP-8, SOT23-5 and SOIC-8 packages; the dual OPA2388 is offered in the VSSOP-8 and SO-8 packages; and the quad OPA4388 is packaged in TSSOP-14 and SO-14 enclosures. The OPA388 is $0.98 in 1,000-unit quantities in a 4.9-mm × 3.9-mm small-outline integrated circuit (SOIC) package. All three versions (singe, dual, quad) are specified over the extended industrial temperature range (-40° C to +125° C).
For more information about the OPAx388 devices, visit www.ti.com/opa388-pr.