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

9.3.3 Full-Scale Range (FSR) and LSB Size

A programmable gain amplifier (PGA) is implemented before the ΔΣ ADC of the ADS1114 and ADS1115. The full-scale range is configured by bits PGA[2:0] in the Config register and can be set to ±6.144 V, ±4.096 V, ±2.048 V, ±1.024 V, ±0.512 V, ±0.256 V. Table 3 shows the FSR together with the corresponding LSB size. Equation 4 shows how to calculate the LSB size from the selected full-scale range.

Equation 4. LSB = FSR / 216

Table 3. Full-Scale Range and Corresponding LSB Size

FSR LSB SIZE
±6.144 V(1) 187.5 μV
±4.096 V(1) 125 μV
±2.048 V 62.5 μV
±1.024 V 31.25 μV
±0.512 V 15.625 μV
±0.256 V 7.8125 μV
(1) This parameter expresses the full-scale range of the ADC scaling. Do not apply more than VDD + 0.3 V to the analog inputs of the device.

The FSR of the ADS1113 is fixed at ±2.048 V.

Analog input voltages must never exceed the analog input voltage limits given in the Absolute Maximum Ratings. If a VDD supply voltage greater than 4 V is used, the ±6.144 V full-scale range allows input voltages to extend up to the supply. Although in this case (or whenever the supply voltage is less than the full-scale range; for example, VDD = 3.3 V and full-scale range = ±4.096 V), a full-scale ADC output code cannot be obtained. For example, with VDD = 3.3 V and FSR = ±4.096 V, only signals up to VIN = ±3.3 V can be measured. The code range that represents voltages |VIN| > 3.3 V is not used in this case.