Texas Instruments AFE782H1RRUT

Overview

AFE782H1RRUT from Texas Instruments is a 14-bit, low-power, voltage-output DAC with integrated HART® modem, 12-bit diagnostic ADC, and 1.25-V reference-designed for 4–20 mA loop-powered process transmitters. It delivers 0 V to 2.5 V output range, 4-LSB INL at 14 bits, 0.07% FSR TUE over –40°C to +125°C, and operates down to 180 µA quiescent current in industrial automation I/O modules.

For engineers reviewing the AFE782H1RRUT datasheet, AFE782H1RRUT pinout, AFE782H1RRUT application, or AFE782H1RRUT equivalent, this device supports SPI/UART dual-interface control of both DAC and HART functions, enables self-health diagnostics via multiplexed ADC inputs, and meets functional safety design requirements for intrinsic-safe transmitter systems.

Technical Context

The AFE782H1RRUT integrates a monotonic 14-bit DAC with digital slew-rate control, a HART-compliant FSK modem (1200/2200 Hz), and a 12-bit 3.84-kSPS diagnostic ADC sharing internal reference and bias sources. Its architecture includes an arbiter managing concurrent SPI and UART access to DAC and modem registers, plus fault detection via CRC frame checking, windowed watchdog timer, and alarm-triggered fail-safe state transitions.

It features dual power domains: PVDD (2.7–5.5 V) powers analog circuitry including DAC output and ADC, while IOVDD (1.71–5.5 V) sets logic thresholds. The internal 1.2288-MHz oscillator feeds clock outputs and synchronizes HART timing, and REF_EN allows seamless switching between internal and external 1.25-V reference sources.

Key Specifications

Pinout & Package

AFE782H1RRUT is housed in a 4.00 mm × 4.00 mm UQFN-24 (RRU) package with wettable flanks for automated optical inspection. Thermal resistance R_θJA = 103.1°C/W supports operation in high-density PCB layouts without forced airflow.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AFE792H1RRUT, AFE782H1RRUT trades 2 bits of resolution for lower power and cost while retaining identical diagnostic, safety, and HART capabilities; compared with AD5758, it eliminates external HART PHY design effort and reduces PCB area by 45% in HART-enabled transmitters.

Availability

AFE782H1RRUT is available at Aetrix Electronics and suitable for 4–20 mA loop-powered transmitters, PLC analog output modules, and HART-enabled calibration tools requiring stable component supply across extended temperature and long product lifecycles.

Supply support for AFE782H1RRUT 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 leadership in industrial interface and signal chain solutions.

The AFE782H1RRUT belongs to TI's Process Control AFE portfolio, designed specifically to consolidate HART-compliant analog output, diagnostics, and safety-critical monitoring into a single IC for field instrumentation and distributed control systems.

FAQ

What is the maximum DAC update rate supported by AFE782H1RRUT?

The AFE782H1RRUT supports DAC updates at up to 12.5 MHz SPI clock frequency, with minimum sequential update wait time of 2.1 µs. This enables effective update rates exceeding 400 kSPS in burst-mode configurations, though practical settling time (65 µs for ¼–¾ scale) limits sustained precision output to ~15 kSPS in closed-loop control applications using AFE782H1RRUT.

Does AFE782H1RRUT require an external crystal for HART operation?

No. AFE782H1RRUT includes an internal 1.2288-MHz oscillator with ±1% frequency stability over –40°C to +125°C, fully meeting HART physical layer timing requirements. The GPIO0/CLK_OUT pin can route this clock externally if needed, eliminating dependency on external crystals or oscillators in AFE782H1RRUT-based designs.

How does the diagnostic ADC in AFE782H1RRUT support functional safety certification?

The AFE782H1RRUT diagnostic ADC monitors five internal nodes (VREF, VOUT, die temperature, POL_SEL/AIN1, AIN0) with 12-bit resolution and 3.84-kSPS sampling. Its results feed into fault-detection logic that triggers ALARM assertion or fail-safe state transitions - a key element documented in TI's functional safety manual for AFE782H1RRUT to support IEC 61508 SIL-2 system certification.

Can AFE782H1RRUT operate with an external reference instead of the internal 1.25-V source?

Yes. When REF_EN is held low, AFE782H1RRUT disables its internal reference and accepts an external 1.25-V source at VREFIO (Pin 19). The device specifies 1.2–1.3 V input range and 125-kΩ input impedance, enabling compatibility with precision external references like REF5025 or ADR4525 - critical for applications requiring <0.05% FSR TUE beyond AFE782H1RRUT's internal reference capability.

What fault conditions trigger the ALARM pin on AFE782H1RRUT?

The ALARM pin on AFE782H1RRUT asserts low on three independent fault conditions: CRC frame errors in SPI/UART communication, timeout of the windowed watchdog timer, or out-of-range readings from the diagnostic ADC (e.g., VREF drift >10 ppm/°C, VOUT short, or die temperature >130°C). All fault responses are configurable via register settings in AFE782H1RRUT.