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  • AFEx8101 16-Bit and 14-Bit, Low-Power DACs With Voltage Reference and Diagnostic ADC for 4-mA to 20-mA Loop-Powered Applications

    • SLASF21 December   2022 AFE78101 , AFE88101

      PRODUCTION DATA  

  • CONTENTS
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  • AFEx8101 16-Bit and 14-Bit, Low-Power DACs With Voltage Reference and Diagnostic ADC for 4-mA to 20-mA Loop-Powered Applications
  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1  Absolute Maximum Ratings
    2. 6.2  ESD Ratings
    3. 6.3  Recommended Operating Conditions
    4. 6.4  Thermal Information
    5. 6.5  Electrical Characteristics
    6. 6.6  Timing Requirements
    7. 6.7  Timing Diagrams
    8. 6.8  Typical Characteristics: VOUT DAC
    9. 6.9  Typical Characteristics: ADC
    10. 6.10 Typical Characteristics: Reference
    11. 6.11 Typical Characteristics: Power Supply
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Digital-to-Analog Converter (DAC) Overview
        1. 7.3.1.1 DAC Resistor String
        2. 7.3.1.2 DAC Buffer Amplifier
        3. 7.3.1.3 DAC Transfer Function
        4. 7.3.1.4 DAC Gain and Offset Calibration
        5. 7.3.1.5 Programmable Slew Rate
        6. 7.3.1.6 DAC Register Structure and CLEAR State
      2. 7.3.2 Analog-to-Digital Converter (ADC) Overview
        1. 7.3.2.1 ADC Operation
        2. 7.3.2.2 ADC Custom Channel Sequencer
        3. 7.3.2.3 ADC Synchronization
        4. 7.3.2.4 ADC Offset Calibration
        5. 7.3.2.5 External Monitoring Inputs
        6. 7.3.2.6 Temperature Sensor
        7. 7.3.2.7 Self-Diagnostic Multiplexer
        8. 7.3.2.8 ADC Bypass
      3. 7.3.3 Programmable Out-of-Range Alarms
        1. 7.3.3.1 Alarm Action Configuration Register
        2. 7.3.3.2 Alarm Voltage Generator
        3. 7.3.3.3 Temperature Sensor Alarm Function
        4. 7.3.3.4 Internal Reference Alarm Function
        5. 7.3.3.5 ADC Alarm Function
        6. 7.3.3.6 Fault Detection
      4. 7.3.4 IRQ
      5. 7.3.5 Internal Reference
      6. 7.3.6 Integrated Precision Oscillator
      7. 7.3.7 One-Time Programmable (OTP) Memory
    4. 7.4 Device Functional Modes
      1. 7.4.1 DAC Power-Down Mode
      2. 7.4.2 Reset
    5. 7.5 Programming
      1. 7.5.1 Communication Setup
        1. 7.5.1.1 SPI Mode
        2. 7.5.1.2 UART Mode
      2. 7.5.2 Serial Peripheral Interface (SPI)
        1. 7.5.2.1 SPI Frame Definition
        2. 7.5.2.2 SPI Read and Write
        3. 7.5.2.3 Frame Error Checking
        4. 7.5.2.4 Synchronization
      3. 7.5.3 UART
        1. 7.5.3.1 UART Break Mode (UBM)
      4. 7.5.4 Status Bits
      5. 7.5.5 Watchdog Timer
    6. 7.6 Register Maps
      1. 7.6.1 AFEx8101 Registers
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Multichannel Configuration
    2. 8.2 Typical Application
      1. 8.2.1 4-mA to 20-mA Current Transmitter
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Start-Up Circuit
          2. 8.2.1.2.2 Current Loop Control
          3. 8.2.1.2.3 Input Protection and Rectification
          4. 8.2.1.2.4 System Current Budget
        3. 8.2.1.3 Application Curves
    3. 8.3 Initialization Set Up
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  9. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  10. 10Mechanical, Packaging, and Orderable Information
  11. IMPORTANT NOTICE

Package Options

Mechanical Data (Package|Pins)
  • RRU|24
    • MPQF588
Thermal pad, mechanical data (Package|Pins)
Orderable Information
  • slasf21_oa
  • slasf21_pm
search No matches found.
  • Full reading width
    • Full reading width
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    • Expanded reading width
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DATA SHEET

AFEx8101 16-Bit and 14-Bit, Low-Power DACs With Voltage Reference and Diagnostic ADC for 4-mA to 20-mA Loop-Powered Applications

1 Features

  • Functional Safety-Capable
    • Documentation available to aid functional safety system design: AFE88101, AFE78101
  • Low quiescent current: 170 µA (typ)
  • 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
  • Internal 1.2288-MHz oscillator with clock output
  • Digital interfaces:
    • Serial peripheral interface (SPI)
    • Universal asynchronous receiver-transmitter (UART)
  • Fault detection: CRC bit error checking, windowed watchdog timer, diagnostic ADC
  • Wide operating temperature: –55°C to +125°C

2 Applications

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

3 Description

The 16-bit AFE88101 and 14-bit AFE78101 (AFEx8101) are highly-integrated, high-accuracy, extremely low-power digital-to-analog converters (DACs) with voltage outputs designed for sensor-transmitter applications.

The AFEx8101 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 devices include a 10‑ppm/°C voltage reference and a 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. This check is capable of detecting errors or malfunctions of the internal bias sources, power regulator, voltage reference, DAC output, die temperature, and optional external voltage source. 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 a maximum quiescent current of 210 µA. The devices are specified over the temperature range of –40°C to +125°C, but are functional from –55°C to +125°C.

Device Information
PART NUMBER RESOLUTION PACKAGE(1)
AFE78101 14-bit RRU (UQFN, 24) 4.00 mm × 4.00 mm
AFE88101 16-bit
(1) For all available packages, see the package option addendum at the end of the data sheet.
Functional Block Diagram

4 Revision History

DATE REVISION NOTES
December 2022 * Initial release.

 
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