A programmable instrumentation amplifier for 12-bit resolution systems

Describes the design of and experimental results obtained from a monolithic gain-programmable instrumentation amplifier that attains performance compatible with 12-bit or higher resolution data acquisition systems. Nonlinearity is held to a 0.01 percent worst-case level over the -25 to 85/spl deg/C temperature range for gains of 1-1000, independent of process variations. Input and output voltage noise and offset drift are also reduced to low levels. A novel input overvoltage protection scheme is also described. The amplifier is fabricated on a standard-beta junction isolated bipolar process that has in addition process-compatible ion implanted JFETs and silicon-chromium thin-film resistors.