JAJSNU4A May   2023  – June 2024 AFE78201 , AFE88201

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1  Absolute Maximum Ratings
    2. 5.2  ESD Ratings
    3. 5.3  Recommended Operating Conditions
    4. 5.4  Thermal Information
    5. 5.5  Electrical Characteristics
    6. 5.6  Timing Requirements
    7. 5.7  Timing Diagrams
    8. 5.8  Typical Characteristics: VOUT DAC
    9. 5.9  Typical Characteristics: ADC
    10. 5.10 Typical Characteristics: Reference
    11. 5.11 Typical Characteristics: Power Supply
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Digital-to-Analog Converter (DAC) Overview
        1. 6.3.1.1 DAC Resistor String
        2. 6.3.1.2 DAC Buffer Amplifier
        3. 6.3.1.3 DAC Transfer Function
        4. 6.3.1.4 DAC Gain and Offset Calibration
        5. 6.3.1.5 Programmable Slew Rate
        6. 6.3.1.6 DAC Register Structure and CLEAR State
      2. 6.3.2  Analog-to-Digital Converter (ADC) Overview
        1. 6.3.2.1 ADC Operation
        2. 6.3.2.2 ADC Custom Channel Sequencer
        3. 6.3.2.3 ADC Synchronization
        4. 6.3.2.4 ADC Offset Calibration
        5. 6.3.2.5 External Monitoring Inputs
        6. 6.3.2.6 Temperature Sensor
        7. 6.3.2.7 Self-Diagnostic Multiplexer
        8. 6.3.2.8 ADC Bypass
      3. 6.3.3  Programmable Out-of-Range Alarms
        1. 6.3.3.1 Alarm-Based Interrupts
        2. 6.3.3.2 Alarm Action Configuration Register
        3. 6.3.3.3 Alarm Voltage Generator
        4. 6.3.3.4 Temperature Sensor Alarm Function
        5. 6.3.3.5 Internal Reference Alarm Function
        6. 6.3.3.6 ADC Alarm Function
        7. 6.3.3.7 Fault Detection
      4. 6.3.4  IRQ
      5. 6.3.5  Internal Reference
      6. 6.3.6  Integrated Precision Oscillator
      7. 6.3.7  Precision Oscillator Diagnostics
      8. 6.3.8  One-Time Programmable (OTP) Memory
      9. 6.3.9  GPIO
      10. 6.3.10 Timer
      11. 6.3.11 Unique Chip Identifier (ID)
      12. 6.3.12 Scratch Pad Register
    4. 6.4 Device Functional Modes
      1. 6.4.1 Register Built-In Self-Test (RBIST)
      2. 6.4.2 DAC Power-Down Mode
      3. 6.4.3 Reset
    5. 6.5 Programming
      1. 6.5.1 Communication Setup
        1. 6.5.1.1 SPI Mode
        2. 6.5.1.2 UART Mode
      2. 6.5.2 GPIO Programming
      3. 6.5.3 Serial Peripheral Interface (SPI)
        1. 6.5.3.1 SPI Frame Definition
        2. 6.5.3.2 SPI Read and Write
        3. 6.5.3.3 Frame Error Checking
        4. 6.5.3.4 Synchronization
      4. 6.5.4 UART Interface
        1. 6.5.4.1 UART Break Mode (UBM)
      5. 6.5.5 Status Bits
      6. 6.5.6 Watchdog Timer
  8. 7 Register Maps
    1. 7.1 AFEx8201 Registers
  9. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Multichannel Configuration
    2. 8.2 Typical Application
      1. 8.2.1 Analog Output Module
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 XTR305
            1. 8.2.1.2.1.1 Current-Output Mode
            2. 8.2.1.2.1.2 Voltage Output Mode
            3. 8.2.1.2.1.3 Diagnostic Features
        3. 8.2.1.3 Application Curves
    3. 8.3 Initialization Setup
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 ドキュメントの更新通知を受け取る方法
    3. 9.3 サポート・リソース
    4. 9.4 Trademarks
    5. 9.5 静電気放電に関する注意事項
    6. 9.6 用語集
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

パッケージ・オプション

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メカニカル・データ（パッケージ｜ピン）
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発注情報

6.3.3.7 Fault Detection

There are two fields within the ADC_CFG register: FLT_CNT and HYST. These fields are applied to the assertion and deassertion of alarm conditions for all the ADC channels.

ADC_CFG.FLT_CNT determines the maximum number of accepted consecutive failures before an alarm condition is reported. For example, if ADC_CFG.FLT_CNT is set for two counts, then three consecutive conversions must be outside of the thresholds to trigger an alarm. Each failure counts towards the FLT_CNT limit even if the failures alternate between high threshold and low threshold.

ADC_CFG.HYST sets the hysteresis used by the alarm-detection circuit. After an alarm is triggered, the hysteresis is applied before the alarm condition is released. In the case of the high threshold, the hysteresis is subtracted from the threshold value. In the case of the low threshold limit, the hysteresis is added to the threshold value.

Channels AIN0, AIN1, and TEMP have high and low thresholds associated with them. If a conversion value falls outside of these limits (that is, if TEMP < low threshold or TEMP > high threshold), an alarm condition for that channel is set. The alarms are disabled by setting 0x000 for the low threshold and 0xFFF for the high threshold, respectively. These alarms are disabled by default. Because the configuration fields for the thresholds are only eight bits wide, the four LSBs are hardcoded for each threshold. The high thresholds four LSBs are hardcoded to 0xF, and the low thresholds four LSBs are hardcoded to 0x0.

All the self diagnostic (SD) channels have fixed thresholds, except SD4, which measures the VOUT of the main DAC. The threshold for SD4 tracks the VOUT with respect to the DAC code. Table 6-5 shows the calculations used to determine the high and low ADC thresholds for each SD channel. The limits in the two right-most columns are determined by the threshold columns to the left and given some margin. The four LSBs are assigned as described previously.

Table 6-5 Self Diagnostic (SD) Alarm ADC Thresholds
SD ADC
INPUT		 ACCEPTED LOW VALUE ACCEPTED HIGH VALUE LOW THRESHOLD HIGH THRESHOLD ADC LOW (HEX) ADC HIGH (HEX)
SD0 VREF/2 VREF/2 – 9% – 25 mV VREF/2 + 9% + 25 mV 0.54375 V 0.70625 V 0x6D0 0x92F
SD1 PVDD/6 1.65/6 – 25 mV 6/6 + 25 mV 0.25 V 1.025 V 0x310 0xD3F
SD2 VDD/2 1.6/2 – 25 mV 2/2 + 25 mV 0.775 V 1.025 V 0x9C0 0xD3F
SD3 0.6 V 0.6 V – 9% – 25 mV 0.6 V + 9% + 25 mV 0.521 V 0.679 V 0x690 0x8CF
SD4 VOUT/2 VOUT/2 – 6 mV VOUT/2 + 6 mV VOUT – 12 mV VOUT + 12 mV Expected – 0x040 Expected + 0x040

The alarm threshold for the SD4 input depends on the expected ADC measurement based on the DAC code. Equation 9 shows the expected ADC code for SD4.

Equation 9. ADC Expected Code = DAC_CODE[MSB:MSB-11]