JAJSHX7A September   2010  – September 2019 ADS7947 , ADS7948 , ADS7949

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     ADS794x のブロック図
  4. 4 改訂履歴
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1  Absolute Maximum Ratings
    2. 7.2  ESD Ratings
    3. 7.3  Recommended Operating Conditions: ADS794x (12-, 10-, 8-Bit)
    4. 7.4  Thermal Information
    5. 7.5  Electrical Characteristics: ADS7947 (12-Bit)
    6. 7.6  Electrical Characteristics: ADS7948 (10-Bit)
    7. 7.7  Electrical Characteristics: ADS7949 (8-Bit)
    8. 7.8  Timing Requirements
    9. 7.9  Switching Characteristics
    10. 7.10 Typical Characteristics: ADS7947, ADS7948, ADS7949
    11. 7.11 Typical Characteristics: ADS7947 (12-Bit)
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Multiplexer and ADC Input
      2. 8.3.2 Reference
      3. 8.3.3 Clock
      4. 8.3.4 ADC Transfer Function
      5. 8.3.5 Power-Down
    4. 8.4 Device Functional Modes
      1. 8.4.1 Device Operation
    5. 8.5 Programming
      1. 8.5.1 16-Clock Frame
      2. 8.5.2 32-Clock Frame
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Driving an ADC Without a Driving Op Amp
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12デバイスおよびドキュメントのサポート
    1. 12.1 関連リンク
    2. 12.2 ドキュメントの更新通知を受け取る方法
    3. 12.3 コミュニティ・リソース
    4. 12.4 商標
    5. 12.5 静電気放電に関する注意事項
    6. 12.6 Glossary
  13. 13メカニカル、パッケージ、および注文情報

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）
サーマルパッド・メカニカル・データ
発注情報

11.2 Layout Example

A common ground plane for both analog and digital often gives better results. Typically, the second PCB layer is the ground plane. The ADC ground pins are returned to the ground plane through multiple vias (PTH). Good practice is to place analog components on one side and digital components on other side of the ADC (or ADCs). All signals must be routed, assuming there is a split ground plane for analog and digital. Furthermore, splitting the ground initially during layout is better. Route all analog and digital traces so that the traces see the respective ground all along the second layer. Then short both grounds to form a common ground plane. Figure 56 shows a typical layout around the ADC.

ADS7947 ADS7948 ADS7949 ai_silk_top_las708.gifFigure 56. Recommended ADC Layout
(Only top layer is shown, second layer is common ground for analog and digital)