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AFE781H1
  • AFE781H1
  • AFE781H1

AFE781H1

ACTIVE

14-bit low-power analog front end (AFE) with DAC, ADC and HART® modem for sensor transmitters

Texas Instruments AFE781H1 Product Info

1 April 2026 0

Parameters

Resolution (Bits)

14

Number of DAC channels

1

Interface type

SPI

Output type

Voltage

Output voltage range (V)

0.15 to 1.25, 0.2 to 1.0, 0.3 to 2.5, 0.4 to 2.0

Reference type

INT/EXT

Architecture

STRING

Rating

Catalog

Features

4-20mA loop transmitter, HART, HART Modem

Power consumption (typ) (mW)

0.342

Operating temperature range (°C)

-55 to 125

Product type

Special-function DAC

ADC resolution (bps)

12

DAC resolution (bps)

14

Package

UQFN (RRU)-24-16 mm² 4 x 4

Features

  • Functional Safety-Capable
    • Documentation available to aid functional safety system design: AFE881H1, AFE781H1
  • Low quiescent current: 180 µA (typical)
  • HART-compliant physical layer modem
  • 16-bit or 14-bit monotonic high-performance DAC
    • 1.8-V supply: 0.15 V to 1.25 V, 0.2 V to 1.0 V
    • 5-V supply: 0.3 V to 2.5 V, 0.4 V to 2.0 V
    • 4-LSB INL at 16 bits
    • 0.07% FSR (max) TUE from –40°C to +125°C
  • 12-bit 3.84-kSPS ADC for advanced diagnostics
  • Integrated 1.25-V reference at 10 ppm/°C (max)
  • Internal 1.2288-MHz oscillator with clock output
  • Digital interface
    • Serial peripheral interface (SPI): Shared bus for both DAC and HART
    • Universal asynchronous receiver-transmitter (UART): Shared bus for both DAC and HART
    • Both: SPI for DAC and UART for HART
  • Fault detection: CRC bit error checking, windowed watchdog timer, diagnostic ADC
  • Digital DAC slew-rate control
  • Wide operating temperature: –55°C to +125°C
  • Functional Safety-Capable
    • Documentation available to aid functional safety system design: AFE881H1, AFE781H1
  • Low quiescent current: 180 µA (typical)
  • HART-compliant physical layer modem
  • 16-bit or 14-bit monotonic high-performance DAC
    • 1.8-V supply: 0.15 V to 1.25 V, 0.2 V to 1.0 V
    • 5-V supply: 0.3 V to 2.5 V, 0.4 V to 2.0 V
    • 4-LSB INL at 16 bits
    • 0.07% FSR (max) TUE from –40°C to +125°C
  • 12-bit 3.84-kSPS ADC for advanced diagnostics
  • Integrated 1.25-V reference at 10 ppm/°C (max)
  • Internal 1.2288-MHz oscillator with clock output
  • Digital interface
    • Serial peripheral interface (SPI): Shared bus for both DAC and HART
    • Universal asynchronous receiver-transmitter (UART): Shared bus for both DAC and HART
    • Both: SPI for DAC and UART for HART
  • Fault detection: CRC bit error checking, windowed watchdog timer, diagnostic ADC
  • Digital DAC slew-rate control
  • Wide operating temperature: –55°C to +125°C

Description

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.

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.

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