MAX1458

19-1373; Rev 0; 5/98 1%-Accurate, Digitally Trimmed Sensor Signal Conditioner General Description The MAX1458 highly integrated analog-sensor signal processor is optimized for piezoresistive sensor calibration and compensation without any external components. It includes a programmable current source for sensor excitation, a 3-bit programmable-gain amplifier (PGA), a 128-bit internal EEPROM, and four 12-bit DACs. Achieving a total error factor within 1% of the sensor’s repeatability errors, the MAX1458 compensates offset, offset temperature coefficient, full-span output (FSO), FSO temperature coefficient (FSOTC), and FSO nonlinearity of silicon piezoresistive sensors. The MAX1458 calibrates and compensates first-order temperature errors by adjusting the offset and span of the input signal via digital-to-analog converters (DACs), thereby eliminating quantization noise. Built-in testability features on the MAX1458 result in the integration of three traditional sensor-manufacturing operations into one automated process: Pretest: Data acquisition of sensor performance under the control of a host test computer. Calibration and compensation: Computation and storage (in an internal EEPROM) of calibration and compensation coefficients computed by the test computer and downloaded to the MAX1458. Final test operation: Verification of transducer calibration and compensation without removal from the pretest socket. Although optimized for use with piezoresistive sensors, the MAX145...