The TI Design TIDA-00247 is a single-chip, two-wire RTD temperature transmitter design based on the 4-20 mA current loop. Before discussing the details of the design it is necessary to understand what a current loop solution is. Current designs use external ADCs, op amps, and DACs, along with a microcontroller to achieve the current loop solution. However, this can also be accomplished with an integrated microcontroller.