JAJSEC5E December   2011  – December 2022 ADS1113-Q1 , ADS1114-Q1 , ADS1115-Q1

PRODUCTION DATA  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 Revision History
    1.     Device Comparison Table
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Timing Requirements: I2C
    7. 6.7 Timing Diagram
    8. 6.8 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Noise Performance
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagrams
    3. 8.3 Feature Description
      1. 8.3.1 Multiplexer
      2. 8.3.2 Analog Inputs
      3. 8.3.3 Full-Scale Range (FSR) and LSB Size
      4. 8.3.4 Voltage Reference
      5. 8.3.5 Oscillator
      6. 8.3.6 Output Data Rate and Conversion Time
      7. 8.3.7 Digital Comparator (ADS1114-Q1 and ADS1115-Q1 Only)
      8. 8.3.8 Conversion Ready Pin (ADS1114-Q1 and ADS1115-Q1 Only)
      9. 8.3.9 SMBus のアラート応答
    4. 8.4 Device Functional Modes
      1. 8.4.1 Reset and Power-Up
      2. 8.4.2 Operating Modes
        1. 8.4.2.1 Single-Shot Mode
        2. 8.4.2.2 Continuous-Conversion Mode
      3. 8.4.3 Duty Cycling For Low Power
    5. 8.5 Programming
      1. 8.5.1 I2C Interface
        1. 8.5.1.1 I2C Address Selection
        2. 8.5.1.2 I2C General Call
        3. 8.5.1.3 I2C Speed Modes
      2. 8.5.2 Target Mode Operations
        1. 8.5.2.1 Receive Mode
        2. 8.5.2.2 Transmit Mode
      3. 8.5.3 Writing To and Reading From the Registers
      4. 8.5.4 Data Format
    6. 8.6 Register Map
      1. 8.6.1 Address Pointer Register (address = N/A) [reset = N/A]
      2. 8.6.2 Conversion Register (P[1:0] = 00b) [reset = 0000h]
      3. 8.6.3 Config Register (P[1:0] = 01b) [reset = 8583h]
      4. 8.6.4 Lo_thresh (P[1:0] = 10b) [reset = 8000h] and Hi_thresh (P[1:0] = 11b) [reset = 7FFFh] Registers
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Basic Connections
      2. 9.1.2 Single-Ended Inputs
      3. 9.1.3 Input Protection
      4. 9.1.4 Unused Inputs and Outputs
      5. 9.1.5 Analog Input Filtering
      6. 9.1.6 Connecting Multiple Devices
      7. 9.1.7 Quick-Start Guide
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Shunt Resistor Considerations
        2. 9.2.2.2 Operational Amplifier Considerations
        3. 9.2.2.3 ADC Input Common-Mode Considerations
        4. 9.2.2.4 Resistor (R1, R2, R3, R4) Considerations
        5. 9.2.2.5 Noise and Input Impedance Considerations
        6. 9.2.2.6 First-Order RC Filter Considerations
        7. 9.2.2.7 Circuit Implementation
        8. 9.2.2.8 Results Summary
      3. 9.2.3 Application Curves
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 Power-Supply Sequencing
      2. 9.3.2 Power-Supply Decoupling
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
      2. 9.4.2 Layout Example
  10. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 サポート・リソース
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  11. 11Mechanical, Packaging, and Orderable Information

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

9.2.2.7 Circuit Implementation

Table 9-2 shows the chosen values for this design.

Table 9-2 Parameters
PARAMETER VALUE
VCM 2.5 V
FSR of ADC ±0.256 V
Output data rate 250 SPS
R1, R3 1 kΩ(1)
R2, R4 5 kΩ(1)
R5, R6 100 Ω(1)
CDIFF 0.22 µF
CCM1, CCM2 0.022 µF
(1) 1% precision resistors used.

Using Equation 7, if VSHUNT ranges from –50 mV to +50 mV, the application circuit produces a differential voltage ranging from –0.250 V to +0.250 V across the ADC inputs. The ADC is therefore configured at a FSR of ±0.256 V to maximize the dynamic range of the ADC.

The –3 dB cutoff frequencies of the differential low-pass filter and the common-mode low-pass filters are set at 3.6 kHz and 0.36 kHz, respectively.

RSHUNT typically ranges from 0.01 mΩ to 100 mΩ. Therefore, if R1 = R3 = 1 kΩ, a good trade-off exists between the circuit input impedance and input referred resistor noise as explained in the Section 9.2.2.5 section.

A simple resistor divider followed by a buffer amplifier is used to generate VCM of 2.5 V from a 5-V supply.