JAJS373D May   2009  – January 2018 ADS1113 , ADS1114 , ADS1115

PRODUCTION DATA.  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
    1.     Device Images
      1.      概略ブロック図
  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
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Timing Requirements: I2C
    7. 7.7 Typical Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Noise Performance
  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
      7. 9.3.7 Digital Comparator (ADS1114 and ADS1115 Only)
      8. 9.3.8 Conversion Ready Pin (ADS1114 and ADS1115 Only)
      9. 9.3.9 SMbus Alert Response
    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 Mode
        2. 9.4.2.2 Continuous-Conversion Mode
      3. 9.4.3 Duty Cycling For Low Power
    5. 9.5 Programming
      1. 9.5.1 I2C Interface
        1. 9.5.1.1 I2C Address Selection
        2. 9.5.1.2 I2C General Call
        3. 9.5.1.3 I2C Speed Modes
      2. 9.5.2 Slave Mode Operations
        1. 9.5.2.1 Receive Mode
        2. 9.5.2.2 Transmit Mode
      3. 9.5.3 Writing To and Reading From the Registers
      4. 9.5.4 Data Format
    6. 9.6 Register Map
      1. 9.6.1 Address Pointer Register (address = N/A) [reset = N/A]
        1. Table 6. Address Pointer Register Field Descriptions
      2. 9.6.2 Conversion Register (P[1:0] = 0h) [reset = 0000h]
        1. Table 7. Conversion Register Field Descriptions
      3. 9.6.3 Config Register (P[1:0] = 1h) [reset = 8583h]
        1. Table 8. Config Register Field Descriptions
      4. 9.6.4 Lo_thresh (P[1:0] = 2h) [reset = 8000h] and Hi_thresh (P[1:0] = 3h) [reset = 7FFFh] Registers
        1. Table 9. Lo_thresh and Hi_thresh Register Field Descriptions
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Basic Connections
      2. 10.1.2 Single-Ended Inputs
      3. 10.1.3 Input Protection
      4. 10.1.4 Unused Inputs and Outputs
      5. 10.1.5 Analog Input Filtering
      6. 10.1.6 Connecting Multiple Devices
      7. 10.1.7 Quickstart Guide
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Shunt Resistor Considerations
        2. 10.2.2.2 Operational Amplifier Considerations
        3. 10.2.2.3 ADC Input Common-Mode Considerations
        4. 10.2.2.4 Resistor (R1, R2, R3, R4) Considerations
        5. 10.2.2.5 Noise and Input Impedance Considerations
        6. 10.2.2.6 First-order RC Filter Considerations
        7. 10.2.2.7 Circuit Implementation
        8. 10.2.2.8 Results Summary
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
    1. 11.1 Power-Supply Sequencing
    2. 11.2 Power-Supply Decoupling
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13デバイスおよびドキュメントのサポート
    1. 13.1 ドキュメントのサポート
      1. 13.1.1 関連資料
    2. 13.2 関連リンク
    3. 13.3 ドキュメントの更新通知を受け取る方法
    4. 13.4 コミュニティ・リソース
    5. 13.5 商標
    6. 13.6 静電気放電に関する注意事項
    7. 13.7 Glossary
  14. 14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

10.1.5 Analog Input Filtering

Analog input filtering serves two purposes:

  1. Limits the effect of aliasing during the sampling process
  2. Reduces external noise from being a part of the measurement

Aliasing occurs when frequency components are present in the input signal that are higher than half the sampling frequency of the ADC (also known as the Nyquist frequency). These frequency components fold back and show up in the actual frequency band of interest below half the sampling frequency. The filter response of the digital filter repeats at multiples of the sampling frequency, also known as the modulator frequency (fMOD), as shown in Figure 41. Signals or noise up to a frequency where the filter response repeats are attenuated to a certain amount by the digital filter depending on the filter architecture. Any frequency components present in the input signal around the modulator frequency, or multiples thereof, are not attenuated and alias back into the band of interest, unless attenuated by an external analog filter.

ADS1113 ADS1114 ADS1115 AliasingEffect_bas683.gifFigure 41. Effect of Aliasing

Many sensor signals are inherently band-limited; for example, the output of a thermocouple has a limited rate of change. In this case, the sensor signal does not alias back into the pass-band when using a ΔΣ ADC. However, any noise pick-up along the sensor wiring or the application circuitry can potentially alias into the pass-band. Power line-cycle frequency and harmonics are one common noise source. External noise can also be generated from electromagnetic interference (EMI) or radio frequency interference (RFI) sources, such as nearby motors and cellular phones. Another noise source typically exists on the printed-circuit-board (PCB) itself in the form of clocks and other digital signals. Analog input filtering helps remove unwanted signals from affecting the measurement result.

A first-order resistor-capacitor (RC) filter is (in most cases) sufficient to either totally eliminate aliasing, or to reduce the effect of aliasing to a level within the noise floor of the sensor. Ideally, any signal beyond fMOD / 2 is attenuated to a level below the noise floor of the ADC. The digital filter of the ADS111x attenuate signals to a certain degree, as shown in Figure 21. In addition, noise components are usually smaller in magnitude than the actual sensor signal. Therefore, use a first-order RC filter with a cutoff frequency set at the output data rate or 10x higher as a generally good starting point for a system design.