Texas Instruments AFE78101RRUR

Overview

AFE78101RRUR from Texas Instruments is a 14-bit, low-power, loop-powered DAC IC with integrated 1.25-V reference, 12-bit diagnostic ADC, and UART/SPI interfaces-designed for 4-mA to 20-mA transmitter systems. It delivers 4-LSB INL, 0.07% FSR TUE over –40°C to +125°C, 170 µA quiescent current, and operates from 1.71 V supply. Used in smart transmitters where self-diagnostic capability and functional safety support are required.

For engineers reviewing the AFE78101RRUR datasheet, AFE78101RRUR pinout, AFE78101RRUR application, or AFE78101RRUR equivalent, this page provides verified technical context, real-world design meaning of key specs, validated pin functions, application-specific implementation insights, and two confirmed alternative parts for 4–20 mA loop transmitter designs.

Technical Context

The AFE78101RRUR integrates a monotonic 14-bit voltage-output DAC with programmable output ranges (e.g., 0.15 V–1.25 V at 1.8 V supply), a 12-bit 3.84-kSPS diagnostic ADC multiplexed across internal nodes (temperature sensor, bias sources, VREF, VOUT), and a 1.2288-MHz internal oscillator with CLK_OUT capability. Its dual-supply architecture separates PVDD (1.71–5.5 V) for analog/ADC/DAC power and IOVDD (1.71–5.5 V) for digital interface logic.

Functional safety features include CRC frame-error checking, windowed watchdog timer, and alarm-triggered fail-safe states (NAMUR-compliant or user-defined). The device supports both SPI (up to 12.5 MHz, Mode 1/2) and UART (9600 baud) communication, with ALARM as open-drain output and IRQ configurable on SDO or UARTOUT.

Key Specifications

Pinout & Package

AFE78101RRUR is housed in a 24-pin UQFN package (RRU), 4.00 mm × 4.00 mm, with wettable flanks and 0.4-mm pitch. Thermal resistance R_θJA = 103.1°C/W supports operation up to +125°C ambient in compact loop-powered enclosures.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DAC-with-diagnostics applications.

Compared with AFE78101RRUR, AFE7800IRGZT requires external reference and diagnostic circuitry-increasing layout complexity and calibration burden-while AD5758ACPZ-RL7 eliminates external V-to-I conversion but removes autonomous fault detection, making it unsuitable for SIL-2 functional safety architectures relying on internal diagnostics.

Availability

AFE78101RRUR is available at Aetrix Electronics and suitable for smart transmitter design, PLC analog output modules, and process control valve positioners requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for industrial deployments.

Supply support for AFE78101RRUR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of expertise in precision data converters and industrial interface solutions.

The AFE78101RRUR belongs to TI's AFEx8101 family of loop-powered analog front-ends, engineered specifically for 4–20 mA sensor transmitters needing integrated diagnostics, ultra-low power, and functional safety compliance.

FAQ

What is the maximum operating temperature range for the AFE78101RRUR?

The AFE78101RRUR is fully specified from –40°C to +125°C and remains functional down to –55°C. Its thermal alarm triggers at 130°C with 5°C absolute accuracy, and the device maintains 0.07% FSR total unadjusted error across the full –40°C to +125°C range-critical for outdoor or high-ambient industrial environments where the AFE78101RRUR operates inside sealed transmitter housings.

Does the AFE78101RRUR support both SPI and UART simultaneously?

No-the AFE78101RRUR supports SPI and UART as independent interface modes, not concurrently. SPI uses CS/SDI/SDO/SCLK pins; UART uses UARTIN/UARTOUT. The IRQ function can be assigned to either SDO (SPI mode) or UARTOUT (UART break mode), but the device cannot process commands on both buses at once. This design simplifies firmware integration in microcontroller-based transmitters using the AFE78101RRUR.

How does the diagnostic ADC in the AFE78101RRUR improve system reliability?

The AFE78101RRUR's 12-bit diagnostic ADC continuously monitors internal nodes-including VREF, VOUT, die temperature, bias sources, and POL_SEL/AIN1-detecting drift, shorts, or opens before they cause output errors. When faults are identified, the AFE78101RRUR asserts ALARM and can enter a NAMUR-compliant fail-safe state (e.g., 3.2 mA or 23 mA), enabling predictive maintenance and reducing unplanned downtime in safety-critical process control loops.

Can the AFE78101RRUR operate from a 1.8-V supply without external regulation?

Yes-the AFE78101RRUR operates directly from 1.71 V to 1.89 V on PVDD with VDD supplied externally or generated internally. At 1.8 V, it achieves 170 µA quiescent current and supports DAC output ranges of 0.15 V–1.25 V (RANGE=0) or 0.2 V–1.0 V (RANGE=1), making the AFE78101RRUR ideal for ultra-low-voltage loop-powered transmitters where headroom is constrained.

What is the purpose of the REF_EN pin on the AFE78101RRUR?

The REF_EN pin (Pin 5) is an active-high digital input that enables or disables the internal 1.25-V reference. When high, the AFE78101RRUR drives 1.25 V onto VREFIO; when low, VREFIO becomes an input requiring an external 1.25-V reference. This flexibility allows designers to substitute higher-precision external references in metrology-grade applications while retaining all other AFE78101RRUR functionality.