Texas Instruments AFE881H1RRUR

The 16-bit AFE881H1 and 14-bit AFE781H1 ( AFEx81H1) are highly-integrated, high-accuracy, extremely low-power digital-to-analog converters (DACs) with voltage outputs designed for HART-enabled sensor-transmitter applications.

The AFEx81H1 devices include most of the components required to design a 4?mA to 20?mA, 2?wire (loop-powered) sensor transmitter. In addition to the highly accurate DAC, these parts include a HART-certified FSK modem, 10?ppm/°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. 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 fail-safe state corresponding to a standard NAMUR output value or user-specified custom value, or both.

These devices operate from supplies as low as 1.71 V with 220 µA maximum quiescent current. The devices are specified over the temperature range of –40°C to 125°C, but are functional from –55°C to 125°C.