SBASAM0B March   2024  – November 2024 ADS127L18

PRODMIX  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  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 Switching Characteristics
    8. 5.8 Timing Diagrams
    9. 5.9 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1  Offset Error Measurement
    2. 6.2  Offset Drift Measurement
    3. 6.3  Gain Error Measurement
    4. 6.4  Gain Drift Measurement
    5. 6.5  NMRR Measurement
    6. 6.6  CMRR Measurement
    7. 6.7  PSRR Measurement
    8. 6.8  SNR Measurement
    9. 6.9  INL Error Measurement
    10. 6.10 THD Measurement
    11. 6.11 IMD Measurement
    12. 6.12 SFDR Measurement
    13. 6.13 Noise Performance
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Analog Inputs (AINP, AINN)
        1. 7.3.1.1 Input Range
      2. 7.3.2 Reference Voltage (REFP, REFN)
        1. 7.3.2.1 Reference Voltage Range
      3. 7.3.3 Clock Operation
        1. 7.3.3.1 Clock Dividers
        2. 7.3.3.2 Internal Oscillator
        3. 7.3.3.3 External Clock
      4. 7.3.4 Power-On Reset (POR)
      5. 7.3.5 VCM Output Voltage
      6. 7.3.6 GPIO
      7. 7.3.7 Modulator
      8. 7.3.8 Digital Filter
        1. 7.3.8.1 Wideband Filter
        2. 7.3.8.2 Low-Latency Filter (Sinc)
          1. 7.3.8.2.1 Sinc4 Filter
          2. 7.3.8.2.2 Sinc4 + Sinc1 Cascade Filter
          3. 7.3.8.2.3 Sinc3 Filter
          4. 7.3.8.2.4 Sinc3 + Sinc1 Filter
    4. 7.4 Device Functional Modes
      1. 7.4.1  Reset
        1. 7.4.1.1 RESET Pin
        2. 7.4.1.2 Reset by SPI Register
        3. 7.4.1.3 Reset by SPI Input Pattern
      2. 7.4.2  Idle and Standby Modes
      3. 7.4.3  Power-Down
      4. 7.4.4  Speed Modes
      5. 7.4.5  Synchronization
        1. 7.4.5.1 Synchronized Control Mode
        2. 7.4.5.2 Start/Stop Control Mode
      6. 7.4.6  Conversion-Start Delay Time
      7. 7.4.7  Calibration
        1. 7.4.7.1 Offset Calibration Registers
        2. 7.4.7.2 Gain Calibration Registers
        3. 7.4.7.3 Calibration Procedure
      8. 7.4.8  Data Averaging
      9. 7.4.9  Diagnostics
        1. 7.4.9.1 ERROR Pin and ERR_FLAG Bit
        2. 7.4.9.2 SPI CRC
        3. 7.4.9.3 Register Map CRC
        4. 7.4.9.4 ADC Error
        5. 7.4.9.5 SPI Address Range
        6. 7.4.9.6 SCLK Counter
        7. 7.4.9.7 Clock Counter
        8. 7.4.9.8 Frame-Sync CRC
        9. 7.4.9.9 Self Test
      10. 7.4.10 Frame-Sync Data Port
        1. 7.4.10.1  Data Packet
        2. 7.4.10.2  Data Format
        3. 7.4.10.3  STATUS_DP Header Byte
        4. 7.4.10.4  FSYNC Pin
        5. 7.4.10.5  DCLK Pin
        6. 7.4.10.6  DOUTx Pins
        7. 7.4.10.7  DINx Pins
        8. 7.4.10.8  Time Division Multiplexing
        9. 7.4.10.9  Daisy Chain
        10. 7.4.10.10 DOUTx Timing
    5. 7.5 Programming
      1. 7.5.1 Hardware Programming
      2. 7.5.2 SPI Programming
        1. 7.5.2.1 Chip Select (CS)
        2. 7.5.2.2 Serial Clock (SCLK)
        3. 7.5.2.3 Serial Data Input (SDI)
        4. 7.5.2.4 Serial Data Output (SDO)
      3. 7.5.3 SPI Frame
      4. 7.5.4 Commands
        1. 7.5.4.1 Write Register Command
        2. 7.5.4.2 Read Register Command
      5. 7.5.5 SPI Daisy-Chain
  9. 8 Register Map
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Input Driver
      2. 9.1.2 Antialias Filter
      3. 9.1.3 Reference Voltage
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 AVDD1 and AVSS
      2. 9.3.2 AVDD2
      3. 9.3.3 IOVDD
      4. 9.3.4 CAPA and CAPD
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

7.3.8 Digital Filter

The digital filter bandwidth-limits (filters) and decimates (data rate reduction) the modulator low-resolution data to yield high-resolution, lower-speed ADC output data. The oversampling ratio (OSR) determines the amount of filtering and decimation that affects signal bandwidth, in-band noise, and ADC output data rate. The ADC output data rate is defined by: fDATA = fMOD / OSR.

The ADC provides two filter types: a wideband filter and a low-latency filter. The filters optimize the frequency characteristics (wideband filter - flat passband) or the time-domain characteristics (low-latency filter - fast response time). All ADC channels must be the same filter type, however different data rates are allowed as long as the data rates are in ratios of 2x, where x = 0, 1, 2, 3, and so on. The filter type is programmable by the CHn_CFG2 registers, where n = channel number.