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

6.3.1.2 Programmable Gain Amplifier (PGA)

The ADS981x features a PGA at every analog input channel. The PGA supports single-ended and differential inputs with a bipolar signal swing. Table 6-1 lists the supported analog input ranges. The analog input range can be configured independently for each channel by using the RANGE_CHx register fields in address 0xC2 and address 0xC3.

Table 6-1 Analog Input Ranges
DIFFERENTIAL INPUTS SINGLE-ENDED INPUTS RANGE_CHx CONFIGURATION
±12V ±12V 5
±10V ±10V 4
±7V ±7V 3
±5V ±5V 0
±3.5V ±3.5V 1
±2.5V ±2.5V 2

Each analog input channel features an antialiasing, low-pass filter (LPF) at the output of the PGA. Table 6-2 lists the various programmable LPF options available in the ADS981x corresponding to the analog input range. Figure 5-14 and Figure 5-15 illustrate the frequency responses for low-bandwidth and wide-bandwidth LPF configurations. The analog input bandwidth for the eight analog input channels can be can be selected using the ANA_BW[7:0] bits in address 0xC0 of register bank 1.

Table 6-2 Low-Pass Filter Corner Frequency
LPF ANALOG INPUT RANGE CORNER FREQUENCY (–3dB)
Low-bandwidth All input ranges 21kHz
Wide-bandwidth ±12V 375kHz
±10V 385kHz
±7V 400kHz
±5V 320kHz
±3.5V 240kHz
±2.5V 182kHz