JAJSOX0A March   2024  – June 2024 ADS127L18

ADVANCE INFORMATION  

  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 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 DOUT Pins
        4. 7.4.11.4 DIN Pins
        5. 7.4.11.5 Time Division Multiplexing
        6. 7.4.11.6 Daisy Chain
        7. 7.4.11.7 Data Packet
        8. 7.4.11.8 STATUS_DP Header
        9. 7.4.11.9 Data Port Timing Adjustment
    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 ドキュメントの更新通知を受け取る方法
    3. 10.3 サポート・リソース
    4. 10.4 Trademarks
    5. 10.5 静電気放電に関する注意事項
    6. 10.6 用語集
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Mechanical Data

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

7.3.1.1 Input Range

The ADC channels have independent input ranges defined as VIN = ±VREF or as VIN = ±2VREF. The ±2VREF input range doubles the usable input range when using a 2.5V reference voltage. The ±2VREF input range typically improves dynamic range by +1dB. However, the inputs are required to be driven to the 5V AVDD1 supply rails to achieve full dynamic range (with a 2.5V reference voltage). Compared to operation with a 2.5V reference voltage, dynamic range performance improves with 4.096V (+4dB) or 5V (+6dB) reference voltages. The ±2VREF range selection is internally forced to the ±VREF range when the high-reference range is selected (used for 4.096V or 5V reference voltages). See the CHn_INP_RNG bits of the CHn_CFG1 registers to program the input range.

In some user configurations, the available input range exceeds the power supply voltage. An example is when using a 3V AVDD1 power supply with a 2.5V reference voltage in the ±2VREF mode.

The ADC channels have the option of changing the signal range to an extended operating mode. In extended mode, the signal range increases 25%, providing additional headroom for the signal. Output data are scaled such that the positive and negative full-scale output codes (7FFFFFh and 800000h) occur at:

Equation 17. VIN = ±1.25 × k × VREF

where:

  • k = 1 or 2, depending on the ±VREF or ±2VREF range option

See the CHn_CFG1 register to program the extended range option.

When the signal exceeds 110% standard full-scale range (in the extended range mode), the ADC still provides valid conversions, but SNR performance degrades. This point of the modulator saturation is where noise increases. The MOD_FLAG bit of the frame-sync STATUS byte indicates when modulator saturation is occurring. See the Frame-Sync STATUS byte for details. Figure 7-4 shows SNR performance versus input amplitude in the extended range operation.

ADS127L14 ADS127L18 Extended Range SNR Performance Figure 7-4 Extended Range SNR Performance