Single-Supply, Auto-Zero Sensor Amplifier with Programmable Gain and Offset.

The PGA308 is a programmable analog sensor signal conditioner. The analog signal path amplifies the sensor signal and provides digital calibration for offset and gain. Calibration is done via the 1W pin, a digital One-Wire, UART-compatible interface. For three-terminal sensor modules, 1W may be connected to VOUT and the assembly programmed through the VOUT pin. Gain and offset calibration parameters are stored onboard in seven banks of one-time programmable (OTP) memory. The power-on reset (POR) OTP bank may be programmed a total of four times.

The all-analog signal path contains a 2×2 input multiplexer (mux) to allow electronic sensor lead swapping, a coarse offset adjust, an auto-zero programmable gain instrumentation amplifier (PGA), a fine gain adjust, a fine offset adjust, and a programmable gain output amplifier. Fault monitor circuitry detects and signals sensor burnout, overload, and system fault conditions. Over/under-scale limits provide additional means for system level diagnostics. The dual-use DOUT/VCLAMP pin can be used as a programmable digital output or as a VOUT over-voltage clamp.