SBAS740B October   2015  – May 2020 ADS1118-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      K-Type Thermocouple Measurement Using Integrated Temperature Sensor for Cold-Junction Compensation
  4. 4 Revision History
  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: Serial Interface
    7. 7.7 Switching Characteristics: Serial Interface
    8. 7.8 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 Diagram
    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 Temperature Sensor
        1. 9.3.6.1 Converting from Temperature to Digital Codes
        2. 9.3.6.2 Converting from Digital Codes to Temperature
    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 and Power-Down
        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 Serial Interface
      2. 9.5.2 Chip Select (CS)
      3. 9.5.3 Serial Clock (SCLK)
      4. 9.5.4 Data Input (DIN)
      5. 9.5.5 Data Output and Data Ready (DOUT/DRDY)
      6. 9.5.6 Data Format
      7. 9.5.7 Data Retrieval
        1. 9.5.7.1 32-Bit Data Transmission Cycle
        2. 9.5.7.2 16-Bit Data Transmission Cycle
    6. 9.6 Register Maps
      1. 9.6.1 Conversion Register [reset = 0000h]
        1. Table 6. Conversion Register Field Descriptions
      2. 9.6.2 Config Register [reset = 058Bh]
        1. Table 7. Config Register Field Descriptions
  10. 10Application and Implementation
    1. 10.1 Application Information
      1. 10.1.1 Serial Interface Connections
      2. 10.1.2 GPIO Ports for Communication
      3. 10.1.3 Analog Input Filtering
      4. 10.1.4 Single-Ended Inputs
      5. 10.1.5 Connecting Multiple Devices
      6. 10.1.6 Pseudo Code Example
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
      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. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 Support Resources
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Glossary
  14. 14Mechanical, Packaging, and Orderable Information

9.1 Overview

The ADS1118-Q1 is a very small, low-power, 16-bit, delta-sigma (ΔΣ) analog-to-digital converter (ADC). The ADS1118-Q1 consists of a ΔΣ ADC core with adjustable gain, an internal voltage reference, a clock oscillator, and an SPI. This device is also a highly linear and accurate temperature sensor. All of these features are intended to reduce required external circuitry and improve performance. The Functional Block Diagram section shows the ADS1118-Q1 functional block diagram.

The ADS1118-Q1 ADC core measures a differential signal, VIN, that is the difference of V(AINP) and V(AINN). The converter core consists of a differential, switched-capacitor ΔΣ modulator followed by a digital filter. This architecture results in a very strong attenuation in any common-mode signals. Input signals are compared to the internal voltage reference. The digital filter receives a high-speed bitstream from the modulator and outputs a code proportional to the input voltage.

The ADS1118-Q1 has two available conversion modes: single-shot and continuous-conversion. In single-shot mode, the ADC performs one conversion of the input signal upon request and stores the value to an internal conversion register. The device then enters a power-down state. This mode is intended to provide significant power savings in systems that require only periodic conversions or when there are long idle periods between conversions. In continuous-conversion mode, the ADC automatically begins a conversion of the input signal as soon as the previous conversion is completed. The rate of continuous conversion is equal to the programmed data rate. Data can be read at any time and always reflect the most recently completed conversion.