AFE88101RRUR

ADCs/DACs - Special Purpose Overview

The AFE88101RRUR is a single-channel, low-power analog front-end featuring a 16-bit voltage-output digital-to-analog converter (DAC) and a diagnostic analog-to-digital converter (ADC). Designed for 4-mA to 20-mA loop-powered sensor transmitters, it integrates a 1.25-V reference with 10 ppm/°C drift and an internal 1.2288-MHz oscillator. The device supports SPI and UART interfaces, offering fault detection via CRC checking and a windowed watchdog timer. It operates from a 1.71-V to 5.5-V supply with a typical quiescent current of 170 µA and functions across a temperature range of –55°C to +125°C in a 24-pin UQFN package.

ADCs/DACs - Special Purpose Feature Summary

• 16-bit monotonic DAC with 4-LSB INL and 0.07% FSR total unadjusted error
• Integrated 12-bit diagnostic ADC operating at 3.84 kSPS for self-health checks
• Low static current consumption of 170 µA (typical) at 1.8 V
• Built-in functional safety features including CRC bit error checking and alarm outputs

ADCs/DACs - Special Purpose Applications

• 2-wire transmitter designs
• 4-mA to 20-mA loop-powered applications
• Process control and industrial automation systems
• Smart transmitters and PLC or DCS I/O modules

ADCs/DACs - Special Purpose Procurement Notes

Verify the specific ordering suffix RRUR corresponds to the 24-pin UQFN package configuration. Confirm that the required documentation for functional safety system design is available for the AFE88101 variant. Ensure external components for voltage-to-current conversion are selected to meet intrinsic safety requirements, as the device provides only the voltage output stage.

ADCs/DACs - Special Purpose Selection Notes

Select the AFE88101RRUR when 16-bit resolution is required for high-accuracy applications; the AFE78101 offers 14-bit resolution. Verify power supply constraints, as the internal LDO activates only above 2.7 V on PVDD. For 1.71 V to 1.89 V operation, ensure an external supply is connected to the VDD pin. Check load requirements against the specified resistive and capacitive limits to maintain stability.

ADCs/DACs - Special Purpose Part Context

The AFE88101 belongs to the AFEx8101 family, which also includes the 14-bit AFE78101. Both devices share identical pinouts, interfaces, and diagnostic capabilities, differing primarily in DAC resolution. This family is engineered specifically for integrating most components needed in 2-wire sensor transmitters, reducing external component count compared to standard DACs.

ADCs/DACs - Special Purpose Replacement Considerations

The AFE78101 is a direct pin-compatible alternative within the same family, offering 14-bit resolution instead of 16-bit. No other cross-model substitutes are documented in the provided datasheet.

ADCs/DACs - Special Purpose FAQ

How does the device handle fault conditions?

The AFE88101 can detect faults using the diagnostic ADC, CRC frame-error checking, and a windowed watchdog timer. Upon detection, it can issue an interrupt or enter a fail-safe state corresponding to a standard NAMUR output value or a user-specified custom value.

What is the input voltage range for the diagnostic ADC?

When PVDD equals VDD (1.71 V to 1.89 V), the ADC input range is 0 V to 1.25 V. When PVDD is greater than 2.7 V, the range expands to 0 V to 2.5 V.

Can the internal voltage reference be disabled?

Yes, the internal 1.25-V reference can be disabled by driving the REF_EN pin logic low. In this mode, an external 1.25-V reference must be applied to the VREFIO pin.