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

Package Options

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

7.4.10.8 Time Division Multiplexing

Time division multiplexing (TDM) mode serializes channel data into the data lanes. The number of data lanes are programmable to 1, 2, 4 or 8 for ADS127L18 and 1, 2 or 4 for the ADS127L14. When the number of data lanes is less than the number of channels, the device packs data in TDM mode. The DP_TDM[1:0] bits of the DP_CFG1 register programs the number of data lanes.

The general characteristics of the data lanes are listed below.

  • If the number data lanes are less than eight (ADS127L18) or less than four (ADS127L18), the unused DOUT pins become data inputs to support daisy chaining. The exception is DOUT1 which remains a driven output.
  • The DINx pin numbers correlate to the DOUTx pin numbers for daisy chaining. The data inputs must either be tied low (or high as desired), or driven by a daisy chain device.
  • When a channel is powered down, the data slot occupies the same position with frozen data. The channel ID bits of the STATUS byte remain active.
  • When channels are powered down, the DOUTx pins of the data lanes remain as outputs.

Figure 7-34 shows the one data-lane option for the ADS127L18. DOUT2 through DOUT7 become unused inputs which must not be allowed to float. Apply daisy-chain data to the DIN0 pin. If unused, tie the pin to ground.

ADS127L14 ADS127L18 DP_TDM[1:0] = 00b, One Data Lane (ADS127L18) Figure 7-34 DP_TDM[1:0] = 00b, One Data Lane (ADS127L18)

Figure 7-35 shows the two data-lane option for the ADS127L18 and the one data-lane option for the ADS127L14. DOUT2 through DOUT7 (ADS127L18) and DOUT2, DOUT3 (ADS127L14) become unused inputs which must not be allowed to float. Apply daisy-chain data to the DIN0 pin (ADS127L14) and to DIN0, DIN1 (ADS127L18). If unused, tie the pins to ground.

ADS127L14 ADS127L18 DP_TDM[1:0] = 01b, Two Data Lanes (ADS127L18) or One Data Lane (ADS127L14 ) Figure 7-35 DP_TDM[1:0] = 01b, Two Data Lanes (ADS127L18) or One Data Lane (ADS127L14 )

Figure 7-36 shows the four data-lane option for the ADS127L18 and the two data-lane option for the ADS127L14. DOUT4 through DOUT7 (ADS127L18) become unused inputs which must not be allowed to float. Apply daisy-chain data to DIN0, DIN1 (ADS127L14) and DIN0 through DIN3 (ADS127L18). If unused, tie to ground.

ADS127L14 ADS127L18 DP_TDM[1:0] = 10b, Four Data Lanes (ADS127L18) or Two Data Lanes (ADS127L14 ) Figure 7-36 DP_TDM[1:0] = 10b, Four Data Lanes (ADS127L18) or Two Data Lanes (ADS127L14 )

Figure 7-37 shows the eight data-lane option for the ADS127L18 and four data-lane option for the ADS127L14. DOUT4 through DOUT7 are not available for the ADS127L14. Daisy chaining is not possible for this mode.

ADS127L14 ADS127L18 DP_TDM[1:0] = 11b, Eight Data Lanes (ADS127L18) or Four Data Lanes (ADS127L14 ) Figure 7-37 DP_TDM[1:0] = 11b, Eight Data Lanes (ADS127L18) or Four Data Lanes (ADS127L14 )