Description

This TI Precision Verified Design provides the theory: component selection: simulation: complete PCB schematic & layout: bill of materials: and measured performance of a single-supply: 3-wire RTD acquisition system that accurately measures temperature from  -200 °C - 850 °C.  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 incoorporating the required current sources: programmable gain amplifier: and digitally-controlled multiplexer onto one chip. A chopping" technique is used to minimize the effects of mismatch 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."