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 Multiple Devices: Daisy-Chain Topology for SPI Configuration

Figure 6-12 shows a typical connection diagram showing multiple devices in a daisy-chain topology.

ADS9815 ADS9817 Daisy-Chain Connections for SPI Configuration Figure 6-12 Daisy-Chain Connections for SPI Configuration

The CS and SCLK inputs of all ADCs are connected together and controlled by a single CS and SCLK pin of the controller, respectively. The SDI input pin of the first ADC in the chain (ADC1) is connected to the peripheral IN controller OUT (PICO) pin of the controller, the SDO output pin of ADC1 is connected to the SDI input pin of ADC2, and so on. The SDO output pin of the last ADC in the chain (ADC4) is connected to the peripheral OUT controller IN (POCI) pin of the controller. The data on the PICO pin passes through ADC1 with a 24-SCLK delay, as long as CS is active.

The daisy-chain mode must be enabled after power-up or after the device is reset. Set the daisy-chain length in the DAISY_CHAIN_LEN register to enable daisy-chain mode. The daisy-chain length is the number of ADCs in the chain excluding ADC1. In Figure 6-12, the DAISY_CHAIN_LEN = 3.