SBASAP6 February   2025 ADC3683-EP , ADC3683-SEP

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 - Power Consumption
    6. 5.6 Electrical Characteristics - DC Specifications
    7. 5.7 Electrical Characteristics - AC Specifications
    8. 5.8 Timing Requirements
    9. 5.9 Typical Characteristics - ADC3683
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Analog Input
        1. 7.3.1.1 Analog Input Bandwidth
        2. 7.3.1.2 Analog Front End Design
          1. 7.3.1.2.1 Sampling Glitch Filter Design
          2. 7.3.1.2.2 Analog Input Termination and DC Bias
            1. 7.3.1.2.2.1 AC-Coupling
            2. 7.3.1.2.2.2 DC-Coupling
        3. 7.3.1.3 Auto-Zero Feature
      2. 7.3.2 Clock Input
        1. 7.3.2.1 Single Ended vs Differential Clock Input
        2. 7.3.2.2 Signal Acquisition Time Adjust
      3. 7.3.3 Voltage Reference
        1. 7.3.3.1 Internal voltage reference
        2. 7.3.3.2 External voltage reference (VREF)
        3. 7.3.3.3 External voltage reference with internal buffer (REFBUF/CTRL)
      4. 7.3.4 Digital Down Converter
        1. 7.3.4.1 DDC MUX
        2. 7.3.4.2 Digital Filter Operation
        3. 7.3.4.3 FS/4 Mixing with Real Output
        4. 7.3.4.4 Numerically Controlled Oscillator (NCO) and Digital Mixer
        5. 7.3.4.5 Decimation Filter
        6. 7.3.4.6 SYNC
        7. 7.3.4.7 Output Formatting with Decimation
      5. 7.3.5 Digital Data Path and Interface
        1. 7.3.5.1 Data Path Overview
        2. 7.3.5.2 Output Scrambler
        3. 7.3.5.3 Output Bit Mapper
          1. 7.3.5.3.1 2-Wire Mode
          2. 7.3.5.3.2 1-Wire Mode
          3. 7.3.5.3.3 ½-Wire Mode
        4. 7.3.5.4 Device Configuration Steps
          1. 7.3.5.4.1 Configuration Example
        5. 7.3.5.5 Output Data Format
      6. 7.3.6 Test Pattern
    4. 7.4 Device Functional Modes
      1. 7.4.1 Normal Operation
      2. 7.4.2 Power Down Options
      3. 7.4.3 Digital Channel Averaging
    5. 7.5 Programming
      1. 7.5.1 Configuration using PINs only
      2. 7.5.2 Configuration using the SPI interface
        1. 7.5.2.1 Register Write
        2. 7.5.2.2 Register Read
  9. 8 Application Information Disclaimer
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input Signal Path
        2. 8.2.2.2 Sampling Clock
        3. 8.2.2.3 Voltage Reference
      3. 8.2.3 Application Curves
    3. 8.3 Initialization Set Up
      1. 8.3.1 Register Initialization During Operation
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Register Map
    1. 9.1 Detailed Register Description
  11. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Mechanical Data

7.3.2.2 Signal Acquisition Time Adjust

The ADC3683-xEP includes a register (DLL PDN (0x11, D2) which increases the signal acquisition time window for clock rates below 40MSPS from 25% to 50% of the clock period. Increasing the sampling time provides a longer time for the driving amplifier to settle out the signal which can improve the SNR performance of the system. This register is only be used at or below 40MSPS. When powering down the DLL, the acquisition time tracks the clock duty cycle (50% is recommended).

Table 7-1 Acquisition time vs DLL PDN setting
SAMPLING CLOCK FS (MSPS)DLL PDN (0x11, D2)ACQUISITION TIME (tACQ)
650TS / 4
≤ 401TS / 2