SBAS444E May   2009  – December 2024 ADS1113 , ADS1114 , ADS1115

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5.   Device Comparison Table
  6. 4 Pin Configuration and Functions
  7. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements: I2C
    7. 5.7 Typical Characteristics
  8. 6 Parameter Measurement Information
    1. 6.1 Noise Performance
  9. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1 Multiplexer
      2. 7.3.2 Analog Inputs
      3. 7.3.3 Full-Scale Range (FSR) and LSB Size
      4. 7.3.4 Voltage Reference
      5. 7.3.5 Oscillator
      6. 7.3.6 Output Data Rate and Conversion Time
      7. 7.3.7 Digital Comparator (ADS1114 and ADS1115 Only)
      8. 7.3.8 Conversion Ready Pin (ADS1114 and ADS1115 Only)
      9. 7.3.9 SMbus Alert Response
    4. 7.4 Device Functional Modes
      1. 7.4.1 Reset and Power-Up
      2. 7.4.2 Operating Modes
        1. 7.4.2.1 Single-Shot Mode
        2. 7.4.2.2 Continuous-Conversion Mode
      3. 7.4.3 Duty Cycling For Low Power
    5. 7.5 Programming
      1. 7.5.1 I2C Interface
        1. 7.5.1.1 I2C Address Selection
        2. 7.5.1.2 I2C General Call
        3. 7.5.1.3 I2C Speed Modes
      2. 7.5.2 Target Mode Operations
        1. 7.5.2.1 Receive Mode
        2. 7.5.2.2 Transmit Mode
      3. 7.5.3 Writing To and Reading From the Registers
      4. 7.5.4 Data Format
  10. 8 Registers
    1. 8.1 Register Map
      1. 8.1.1 Address Pointer Register (address = N/A) [reset = N/A]
      2. 8.1.2 Conversion Register (P[1:0] = 00b) [reset = 0000h]
      3. 8.1.3 Config Register (P[1:0] = 01b) [reset = 8583h]
      4. 8.1.4 Lo_thresh (P[1:0] = 10b) [reset = 8000h] and Hi_thresh (P[1:0] = 11b) [reset = 7FFFh] Registers
  11. 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
  12. 10Power Supply Recommendations
    1. 10.1 Power-Supply Sequencing
    2. 10.2 Power-Supply Decoupling
  13. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  14. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  15. 13Revision History
  16. 14Mechanical, Packaging, and Orderable Information

7.3.3 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 ±6.144V, ±4.096V, ±2.048V, ±1.024V, ±0.512V, and ±0.256V. Table 7-1 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 7-1 Full-Scale Range and Corresponding LSB Size
FSRLSB SIZE
±6.144V(1)187.5μV
±4.096V(1)125μV
±2.048V62.5μV
±1.024V31.25μV
±0.512V15.625μV
±0.256V7.8125μV
(1) This parameter expresses the full-scale range of the ADC scaling. Do not apply more than VDD + 0.3V to the analog inputs of the device.

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

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