Single-channel 16-bit voltage analog front end (AFE) for sensor transmitters

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.