JAJSE50 November   2017 TLA2021 , TLA2022 , TLA2024

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      システム監視アプリケーションの例
  4. 4 改訂履歴
  5. 5 概要（続き）
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
    1.     Pin Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 I2C Timing Requirements
    7. 8.7 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagrams
    3. 9.3 Feature Description
      1. 9.3.1 Multiplexer
      2. 9.3.2 Analog Inputs
      3. 9.3.3 Full-Scale Range (FSR) and LSB Size
      4. 9.3.4 Voltage Reference
      5. 9.3.5 Oscillator
      6. 9.3.6 Output Data Rate and Conversion Time
    4. 9.4 Device Functional Modes
      1. 9.4.1 Reset and Power-Up
      2. 9.4.2 Operating Modes
        1. 9.4.2.1 Single-Shot Conversion Mode
        2. 9.4.2.2 Continuous-Conversion Mode
    5. 9.5 Programming
      1. 9.5.1 I2C Interface
        1. 9.5.1.1 I2C Address Selection
        2. 9.5.1.2 I2C Interface Speed
        3. 9.5.1.3 Serial Clock (SCL) and Serial Data (SDA)
        4. 9.5.1.4 I2C Data Transfer Protocol
        5. 9.5.1.5 Timeout
        6. 9.5.1.6 I2C General-Call (Software Reset)
      2. 9.5.2 Reading and Writing Register Data
        1. 9.5.2.1 Reading Conversion Data or the Configuration Register
        2. 9.5.2.2 Writing the Configuration Register
      3. 9.5.3 Data Format
  10. 10Register Maps
    1. 10.1 Conversion Data Register (RP = 00h) [reset = 0000h]
      1. Table 6. Conversion Data Register Field Descriptions
    2. 10.2 Configuration Register (RP = 01h) [reset = 8583h]
      1. Table 7. Configuration Register Field Descriptions
  11. 11Application and Implementation
    1. 11.1 Application Information
      1. 11.1.1 Basic Interface Connections
      2. 11.1.2 Connecting Multiple Devices
      3. 11.1.3 Single-Ended Signal Measurements
      4. 11.1.4 Analog Input Filtering
      5. 11.1.5 Duty Cycling To Reduce Power Consumption
      6. 11.1.6 I2C Communication Sequence Example
    2. 11.2 Typical Application
      1. 11.2.1 Design Requirements
      2. 11.2.2 Detailed Design Procedure
      3. 11.2.3 Application Curve
  12. 12Power Supply Recommendations
    1. 12.1 Power-Supply Sequencing
    2. 12.2 Power-Supply Decoupling
  13. 13Layout
    1. 13.1 Layout Guidelines
    2. 13.2 Layout Example
  14. 14デバイスおよびドキュメントのサポート
    1. 14.1 デバイス・サポート
      1. 14.1.1 デベロッパー・ネットワークの製品に関する免責事項
    2. 14.2 関連リンク
    3. 14.3 ドキュメントの更新通知を受け取る方法
    4. 14.4 コミュニティ・リソース
    5. 14.5 商標
    6. 14.6 静電気放電に関する注意事項
    7. 14.7 Glossary
  15. 15メカニカル、パッケージ、および注文情報

11.1.4 Analog Input Filtering

Analog input filtering serves two purposes:

  1. Limits the effect of aliasing during the ADC sampling process
  2. Attenuates unwanted noise components outside the bandwidth of interest

In most cases, a first-order resistor capacitor (RC) filter is sufficient to completely eliminate aliasing or to reduce the effect of aliasing to a level within the noise floor of the sensor. A good starting point for a system design with the TLA202x is to use a differential RC filter with a cutoff frequency set somewhere between the selected output data rate and 25 kHz. Make the series resistor values as small as possible to reduce voltage drops across the resistors caused by the device input currents to a minimum. However, the resistors should be large enough to limit the current into the analog inputs to less than 10 mA in the event of an overvoltage. Then choose the differential capacitor value to achieve the target filter cutoff frequency. Common-mode filter capacitors to GND can be added as well, but should always be at least ten times smaller than the differential filter capacitor.

Figure 20 shows an example of filtering a differential signal (AIN0, AIN1), and a single-ended signal (AIN3). Equation 3 and Equation 4 show how to calculate the filter cutoff frequencies (fCO) in the differential and single-ended cases, respectively.

Equation 3. fCO DIF = 1 / (2π · 2 · RFLT · CDIF)
Equation 4. fCO SE = 1 / (2π · RFLT · CSE)