Low-power AFE with 14-bit DAC, 12-bit ADC for PLC and sensor transmitter applications

The 16-bit AFE88201 and 14-bit AFE78201 (AFEx8201) are highly-integrated, high-accuracy, extremely low-power digital-to-analog converters (DACs) with voltage outputs designed for process-control and industrial-automation applications.

The AFEx8201 devices include most of the components required to design a 4mA to 20mA, 3‑wire or 4-wire sensor transmitter or analog output module. In addition to the highly accurate DAC, the AFEx8201 incorporate a 10ppm/°C voltage reference and diagnostic analog-to-digital converter (ADC). To accommodate intrinsic and functional-safety concerns, external voltage-to-current conversion and power-regulation are required.

The internal diagnostic ADC is multiplexed to several internal nodes that enable an automatic self-health check. This check is capable of detecting errors or malfunctions of the internal bias sources, power regulator, voltage reference, DAC output, die temperature, and optional external voltage source. If any fault is detected from the diagnostic ADC, CRC frame-error checking, or windowed watchdog timer, the devices can optionally issue an interrupt, enter a user-specified fail-safe state, or both.