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

6.3.6.1 Data Clock Output

The ADS981x features a source-synchronous data interface where the ADC provides the output data and the clock to capture the data. The clock to capture the data is output on the DCLKOUT pin. The clock frequency depends on the sampling clock speed, data rate (SDR or DDR), and number of output lanes (four lanes or two lanes) and is given by Equation 3. The frame clock frequency is given by Equation 4.

Equation 3. D a t a   c l o c k   f r e q u e n c y   =   24   b i t s / c h a n n e l   × 8   c h a n n e l s N u m b e r   o f   d a t a   l a n e s   ×   D a t a   r a t e   ( S D R   =   1 ,   D D R   =   2 ) × Frame   c l o c k   f r e q u e n c y
Equation 4. Frame clock frequency   =    Sampling clock frequency 4

Table 6-8 shows the data clock frequency for the maximum sampling rates for the ADS9817 and ADS9815 for various interface modes.

Table 6-8 Data Clock Frequency for Interface Modes
INTERFACE MODE ADS9815
(fSMPL_CLK = 4MHz)		 ADS9817
(fSMPL_CLK = 8MHz)
4-lane, DDR 24MHz 48MHz
2-lane, DDR 48MHz 96MHz
4-lane, SDR 48MHz 96MHz
2-lane, SDR 96MHz Not supported