Single-Wire 16-bit DAC for 4-20mA Loops

The DAC161P997 is a 16-bit ΣΔ digital-to-analog converter (DAC) for transmitting an analog output current over an industry standard 4-20 mA current loop. It offers 16-bit accuracy with a low output current temperature coefficient (29 ppm/°C) and excellent long-term output current drift (90 ppmFS) while consuming less than 190 µA.

The data link to the DAC161P997 is a Single Wire Interface (SWIF) which allows sensor data to be transferred in digital format over an isolation boundary using a single isolation component. The DAC161P997’s digital input is compatible with standard isolation transformers and opto-couplers. Error detection and handshaking features within the SWIF protocol ensure error free communication across the isolation boundary. For applications where isolation is not required, the DAC161P997 interfaces directly to a microcontroller.

The loop drive of the DAC161P997 interfaces to a HART (Highway Addressable Remote Transducer) modulator, allowing injection of FSK modulated digital data into the 4-20 mA current loop. This combination of specifications and features makes the DAC161P997 ideal for 2- and 4-wire industrial transmitters.

The DAC161P997 is available in a 16-lead WQFN package and is specified over the extended industrial temperature range of –40°C to 105°C.