SBASAM0 March   2024 ADS127L18

ADVANCE INFORMATION  

  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
  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 Internal Oscillator
        2. 7.3.3.2 External Clock
      4. 7.3.4 Power Supplies
        1. 7.3.4.1 AVDD1 and AVSS
        2. 7.3.4.2 AVDD2
        3. 7.3.4.3 IOVDD
        4. 7.3.4.4 Power-On Reset (POR)
        5. 7.3.4.5 CAPA and CAPD
      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
      9. 7.3.9 Low-Latency Filter (Sinc)
        1. 7.3.9.1 Sinc4 Filter
        2. 7.3.9.2 Sinc4 + Sinc1 Cascade Filter
        3. 7.3.9.3 Sinc3 Filter
        4. 7.3.9.4 Sinc3 + Sinc1 Filter
    4. 7.4 Device Functional Modes
      1. 7.4.1  Speed Modes
      2. 7.4.2  Synchronization
        1. 7.4.2.1 Synchronized Control Mode
        2. 7.4.2.2 Start/Stop Control Mode
      3. 7.4.3  Digital Filter Settling
      4. 7.4.4  Conversion-Start Delay Time
      5. 7.4.5  Data Averaging
      6. 7.4.6  Calibration
        1. 7.4.6.1 Offset Calibration Registers
        2. 7.4.6.2 Gain Calibration Registers
        3. 7.4.6.3 Calibration Procedure
      7. 7.4.7  Reset
        1. 7.4.7.1 RESET Pin
        2. 7.4.7.2 Reset by SPI Register
        3. 7.4.7.3 Reset by SPI Input Pattern
      8. 7.4.8  Power-Down
      9. 7.4.9  Idle and Standby Modes
      10. 7.4.10 Diagnostics
        1. 7.4.10.1 ERROR Pin and ERR_FLAG Bit
        2. 7.4.10.2 Clock Counter
        3. 7.4.10.3 SCLK Counter
        4. 7.4.10.4 Frame-Sync CRC
        5. 7.4.10.5 SPI CRC
        6. 7.4.10.6 Register Map CRC
        7. 7.4.10.7 Self Test
      11. 7.4.11 Frame-Sync Data Port
        1. 7.4.11.1 FSYNC Pin
        2. 7.4.11.2 DCLK Pin
        3. 7.4.11.3 DOUTn Pins
        4. 7.4.11.4 DINn Pins
        5. 7.4.11.5 Time Division Multiplexing (TDM)
        6. 7.4.11.6 Data Size
        7. 7.4.11.7 STATUS_DP Header
        8. 7.4.11.8 Daisy Chain
        9. 7.4.11.9 Data Port Offset 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 SPI Commands
        1. 7.5.4.1 Read Register Command
        2. 7.5.4.2 Write 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
    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
    1. 12.1 Mechanical Data

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2.3 Application Curves

The following figures are produced by the TINA-TI™, SPICE-based analog simulation program. Download the THS4551 SPICE model at the THS4551 product folder.

Figure 9-2 shows the frequency response of the antialias filter and the total response of the antialias filter and ADC. As shown in this image, the filter provides 90dB stop-band attenuation from the Nyquist frequency to the 12.8MHz fMOD frequency.

Figure 9-3 shows the analog filter group delay. The 0.575μs group delay is small in comparison to the 85μs group delay of the ADC digital filter (34 / fDATA). The analog filter group delay linearity is 0.017μs, peaking at the edge of the 165kHz pass band.

GUID-E9EFF259-BA2D-47C1-83B1-04D50CFE38E8-low.svgFigure 9-2 Antialias Filter Frequency Response
GUID-A134AD8A-B88B-4551-8D11-9B903EB70FA6-low.pngFigure 9-3 Antialias Filter Group Delay

Figure 9-4 shows the noise density of the antialias filter circuit, the noise density of the ADC, and the combined noise density of the filter and ADC. Noise density is the noise voltage per √Hz of bandwidth plotted versus frequency.

Figure 9-5 shows the total noise from the 1Hz start frequency up to the ADC final bandwidth. Below 200Hz, noise is dominated by 1 / f voltage and current noise of the THS4551 amplifier. Above 200Hz, noise is dominated by ADC noise. The combined noise of the filter and ADC over the 165kHz bandwidth is 11.8μV, meeting the 12μV target value.

GUID-4343DCDA-1393-4171-944A-2897496B7A2D-low.svgFigure 9-4 Noise Density
GUID-2671AB38-B3F5-40B2-AF13-8CC33891A93F-low.svgFigure 9-5 Total Noise