TIPD120, 0-100C, 0.005 %FSR, Ratiometric 3-Wire RTD Acquisition System

TIPD120, Precision Verified Design provides theory, component selection, simulated and measured results of a single-supply, 3-wire RTD acquisition system that accurately measures temperature from 0C - 100C. The voltage input and reference voltage are placed in a ratiometric configuration in order to reduce the errors from noise and drift and improve overall system accuracy. The ADS1247 simplifies the front-end solution by incorporating the required current sources, programmable gain amplifier, and digitally-controlled multiplexer onto one chip. A unique "chopping" technique is used to minimize any difference between the two current sources. The TPS7A4901 adjustable-output, high-PSRR LDO is suggested as a cleaner power alternative over the existing USB supply to further improve system accuracy