JAJSLC0 March   2024 ADC3683-SP

PRODMIX  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  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
  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 Front End Design
          1. 7.3.1.1.1 Sampling Glitch Filter Design
          2. 7.3.1.1.2 Analog Input Termination and DC Bias
            1. 7.3.1.1.2.1 AC-Coupling
            2. 7.3.1.1.2.2 DC-Coupling
        2. 7.3.1.2 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)
      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 Interface
        1. 7.3.5.1 Output Formatter
        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 Output Interface or Mode Configuration
          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 ドキュメントの更新通知を受け取る方法
    2. 10.2 サポート・リソース
    3. 10.3 Trademarks
    4. 10.4 静電気放電に関する注意事項
    5. 10.5 用語集
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Mechanical Data

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
  • HBP|64
サーマルパッド・メカニカル・データ
発注情報

8.4 Power Supply Recommendations

The ADC3683-SP requires two different power-supplies. The AVDD rail provides power for the internal analog circuits and to the ADC while the IOVDD rail powers the digital interface, the internal digital circuits like decimation filter, or the output interface mapper. Power sequencing is not required.

The AVDD power supply must be low noise to achieve data sheet performance. In applications operating near DC, the 1/f noise contribution of the power supply needs to be considered. The ADC is designed for good PSRR which aides with the power supply filter design.

GUID-7ED6981D-1527-43EA-A34E-97618F21B96D-low.gifFigure 8-7 Power Supply Rejection Ratio (PSRR) vs Frequency

There are two recommended power-supply architectures:

  1. Step down using high-efficiency switching converters, followed by a second stage of regulation using a low noise LDO to provide switching noise reduction and improved voltage accuracy.
  2. Directly step down the final ADC supply voltage using high-efficiency switching converters. This approach provides the best efficiency, but care must be taken to make sure switching noise is minimized to prevent degraded ADC performance.

TI WEBENCH® Power Designer can be used to select and design the individual power-supply elements needed: see the WEBENCH® Power Designer

Recommended switching regulators for the first stage include the TPS62821, and similar devices.

Recommended low dropout (LDO) linear regulators include the TPS7A4701, TPS7A90, LP5901, and similar devices.

For the switch regulator only approach, the ripple filter must be designed with a notch frequency that aligns with the switching ripple frequency of the DC/DC converter. Note the switching frequency reported from WEBENCH® and design the EMI filter and capacitor combination to have the notch frequency centered as needed. Figure 8-8 and Figure 8-9 illustrate the two approaches.

AVDD and IOVDD supply voltages should not be shared to prevent digital switching noise from coupling into the analog signal chain.

GUID-B409FB8F-EB3A-422C-83C1-B47036DECF32-low.gifFigure 8-8 Example: LDO Linear Regulator Approach
GUID-6BBBCBD0-0CA8-4676-BF31-73F602188C57-low.gifFigure 8-9 Example Switcher-Only Approach