SBASA81B January   2023  – October 2024 ADS9815 , ADS9817

PRODUCTION DATA  

  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 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Analog Inputs
        1. 6.3.1.1 Input Clamp Protection Circuit
        2. 6.3.1.2 Programmable Gain Amplifier (PGA)
        3. 6.3.1.3 Wide-Common-Mode Voltage Rejection Circuit
        4. 6.3.1.4 Gain Error Calibration
      2. 6.3.2 ADC Transfer Function
      3. 6.3.3 ADC Sampling Clock Input
      4. 6.3.4 Reference
        1. 6.3.4.1 Internal Reference Voltage
        2. 6.3.4.2 External Reference Voltage
      5. 6.3.5 Sample Synchronization
      6. 6.3.6 Data Interface
        1. 6.3.6.1 Data Clock Output
        2. 6.3.6.2 ADC Output Data Randomizer
        3. 6.3.6.3 Test Patterns for Data Interface
          1. 6.3.6.3.1 Fixed Pattern
          2. 6.3.6.3.2 Digital Ramp
          3. 6.3.6.3.3 Alternating Test Pattern
    4. 6.4 Device Functional Modes
      1. 6.4.1 Power-Down
      2. 6.4.2 Reset
      3. 6.4.3 Initialization Sequence
      4. 6.4.4 Normal Operation
    5. 6.5 Programming
      1. 6.5.1 Register Write
      2. 6.5.2 Register Read
      3. 6.5.3 Multiple Devices: Daisy-Chain Topology for SPI Configuration
        1. 6.5.3.1 Register Write With Daisy-Chain
        2. 6.5.3.2 Register Read With Daisy-Chain
  8. 7 Register Map
    1. 7.1 Register Bank 0
    2. 7.2 Register Bank 1
    3. 7.3 Register Bank 2
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Parametric Measurement Unit (PMU)
      2. 8.2.2 Design Requirements
      3. 8.2.3 Detailed Design Procedure
      4. 8.2.4 Application Curve
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Receiving Notification of Documentation Updates
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

6.5.3.2 Register Read With Daisy-Chain

Figure 6-15 illustrates an SPI waveform for reading registers in a daisy-chain configuration. The steps for reading registers from N ADCs connected in a daisy-chain are as follows:

  1. Register read is enabled by writing to the following registers using the Register Write With Daisy-Chain:
    1. Write to PAGE_SEL to select the desired register bank
    2. Enable register read by writing SPI_RD_EN = 0b and SPI_MODE = 0b (default on power-up)
  2. With the register bank selected, the controller can read register data in the following two steps:
    1. N × 24-bit SPI frame containing the 8-bit register address to be read: N-times {0xFE, 0x00, 8-bit register address}
    2. N × 24-bit SPI frame to read out register data: N-times {0xFF, 0xFF, 0xFF}

The 0xFE in step 2a configures the ADC for register read from the specified 8-bit address. At the end of step 2a, the output shift register in the ADC is loaded with register data. The ADC returns the 8-bit register address and corresponding 16-bit register data in step 2b.

ADS9815 ADS9817 Register Read With Daisy-Chain Figure 6-15 Register Read With Daisy-Chain