SBAS752A May 2017  – August 2017 ADS122U04

PRODUCTION DATA. 

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1Absolute Maximum Ratings
    2. 6.2ESD Ratings
    3. 6.3Recommended Operating Conditions
    4. 6.4Thermal Information
    5. 6.5Electrical Characteristics
    6. 6.6UART Timing Requirements
    7. 6.7UART Switching Characteristics
    8. 6.8Typical Characteristics
  7. Parameter Measurement Information
    1. 7.1Noise Performance
  8. Detailed Description
    1. 8.1Overview
    2. 8.2Functional Block Diagram
    3. 8.3Feature Description
      1. 8.3.1 Multiplexer
      2. 8.3.2 Low-Noise Programmable Gain Stage
        1. 8.3.2.1PGA Input Voltage Requirements
        2. 8.3.2.2Bypassing the PGA
      3. 8.3.3 Modulator and Internal Oscillator
      4. 8.3.4 Digital Filter
      5. 8.3.5 Conversion Times
      6. 8.3.6 Voltage Reference
      7. 8.3.7 Excitation Current Sources
      8. 8.3.8 Sensor Detection
      9. 8.3.9 System Monitor
      10. 8.3.10Offset Calibration
      11. 8.3.11Temperature Sensor
        1. 8.3.11.1Converting From Temperature to Digital Codes
          1. 8.3.11.1.1For Positive Temperatures (For Example, 50°C):
          2. 8.3.11.1.2For Negative Temperatures (For Example, -25°C):
        2. 8.3.11.2Converting From Digital Codes to Temperature
      12. 8.3.12Conversion Data Counter
      13. 8.3.13Data Integrity
      14. 8.3.14General-Purpose Digital Inputs/Outputs
    4. 8.4Device Functional Modes
      1. 8.4.1Power-Up and Reset
        1. 8.4.1.1Power-On Reset
        2. 8.4.1.2RESET Pin
        3. 8.4.1.3Reset by Command
      2. 8.4.2Conversion Modes
        1. 8.4.2.1Single-Shot Conversion Mode
        2. 8.4.2.2Continuous Conversion Mode
      3. 8.4.3Operating Modes
        1. 8.4.3.1Normal Mode
        2. 8.4.3.2Turbo Mode
        3. 8.4.3.3Power-Down Mode
    5. 8.5Programming
      1. 8.5.1UART Interface
        1. 8.5.1.1Receive (RX)
        2. 8.5.1.2Transmit (TX)
        3. 8.5.1.3Data Ready (DRDY)
        4. 8.5.1.4Protocol
        5. 8.5.1.5Timeout
        6. 8.5.1.6Data Format
      2. 8.5.2Commands
        1. 8.5.2.1RESET (0000 011x)
        2. 8.5.2.2START/SYNC (0000 100x)
        3. 8.5.2.3POWERDOWN (0000 001x)
        4. 8.5.2.4RDATA (0001 xxxx)
        5. 8.5.2.5RREG (0010 rrrx)
        6. 8.5.2.6WREG (0100 rrrx dddd dddd)
        7. 8.5.2.7Command Latching
      3. 8.5.3Reading Data
        1. 8.5.3.1Manual Data Read Mode
        2. 8.5.3.2Automatic Data Read Mode
      4. 8.5.4Data Integrity
    6. 8.6Register Map
      1. 8.6.1Configuration Registers
      2. 8.6.2Register Descriptions
        1. 8.6.2.1Configuration Register 0 (address = 00h) [reset = 00h]
        2. 8.6.2.2Configuration Register 1 (address = 01h) [reset = 00h]
        3. 8.6.2.3Configuration Register 2 (address = 02h) [reset = 00h]
        4. 8.6.2.4Configuration Register 3 (address = 03h) [reset = 00h]
        5. 8.6.2.5Configuration Register 4 (address = 04h) [reset = 00h]
  9. Application and Implementation
    1. 9.1Application Information
      1. 9.1.1Interface Connections
      2. 9.1.2Analog Input Filtering
      3. 9.1.3External Reference and Ratiometric Measurements
      4. 9.1.4Establishing Proper Limits on the Absolute Input Voltage
      5. 9.1.5Unused Inputs and Outputs
      6. 9.1.6Pseudo Code Example
    2. 9.2Typical Applications
      1. 9.2.1K-Type Thermocouple Measurement (-200°C to +1250°C)
        1. 9.2.1.1Design Requirements
        2. 9.2.1.2Detailed Design Procedure
        3. 9.2.1.3Application Curves
      2. 9.2.23-Wire RTD Measurement (-200°C to +850°C)
        1. 9.2.2.1Design Requirements
        2. 9.2.2.2Detailed Design Procedure
          1. 9.2.2.2.1Design Variations for 2-Wire and 4-Wire RTD Measurements
        3. 9.2.2.3Application Curves
      3. 9.2.3Resistive Bridge Measurement
        1. 9.2.3.1Design Requirements
        2. 9.2.3.2Detailed Design Procedure
  10. 10Power Supply Recommendations
    1. 10.1Power-Supply Sequencing
    2. 10.2Power-Supply Ramp Rate
    3. 10.3Power-Supply Decoupling
  11. 11Layout
    1. 11.1Layout Guidelines
    2. 11.2Layout Example
  12. 12Device and Documentation Support
    1. 12.1Documentation Support
      1. 12.1.1Related Documentation
    2. 12.2Receiving Notification of Documentation Updates
    3. 12.3Community Resources
    4. 12.4Trademarks
    5. 12.5Electrostatic Discharge Caution
    6. 12.6Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Features

  • Current Consumption as Low as 315 µA (typ)
  • Wide Supply Range: 2.3 V to 5.5 V
  • Programmable Gain: 1 to 128
  • Programmable Data Rates: Up to 2 kSPS
  • Up to 20 Bits Effective Resolution
  • Simultaneous 50-Hz and 60-Hz Rejection at 20 SPS With Single-Cycle Settling Digital Filter
  • Two Differential or Four Single-Ended Inputs
  • Dual-Matched Programmable Current Sources:
    10 µA to 1.5 mA
  • Internal 2.048-V Reference: 5 ppm/°C (typ) Drift
  • Internal 2% Accurate Oscillator
  • Internal Temperature Sensor:
    0.5°C (typ) Accuracy
  • Three General-Purpose Inputs/Outputs
  • 2-Wire UART Compatible Interface (8-N-1 Format) With Baud Rates up to 120 kBaud and
    Auto-Baud-Rate Detection
  • Package: 3.0-mm × 3.0-mm × 0.75-mm WQFN

Applications

  • Sensor Transducers and Transmitters:
    Temperature, Pressure, Strain, Flow
  • PLC and DCS Analog Input Modules
  • Temperature Controllers
  • Climate Chambers, Industrial Ovens
  • Patient Monitoring Systems:
    Body Temperature, Blood Pressure

Description

The ADS122U04 is a precision, 24-bit, analog-to-digital converter (ADC) that offers many integrated features to reduce system cost and component count in applications measuring small sensor signals. The device features two differential or four single-ended inputs through a flexible input multiplexer (MUX), a low-noise, programmable gain amplifier (PGA), two programmable excitation current sources, a voltage reference, an oscillator, and a precision temperature sensor.

The device can perform conversions at data rates up to 2000 samples-per-second (SPS) with single-cycle settling. At 20 SPS, the digital filter offers simultaneous 50-Hz and 60-Hz rejection for noisy industrial applications. The internal PGA offers gains up to 128. This PGA makes the ADS122U04 ideally suited for applications measuring small sensor signals, such as resistance temperature detectors (RTDs), thermocouples, thermistors, and resistive bridge sensors.

The ADS122U04 features a 2-wire, UART-compatible interface. In applications that require galvanic isolation this universal asynchronous receiver/transmitter (UART) interface minimizes the number of digital isolation channels, thus saving cost, board space, and power.

The ADS122U04 is offered in a leadless 16-pin WQFN or a 16-pin TSSOP package and is specified over a temperature range of –40°C to +125°C.

Device Information(1)

PART NUMBERPACKAGEBODY SIZE (NOM)
ADS122U04WQFN (16)3.00 mm × 3.00 mm
TSSOP (16)5.00 mm × 4.40 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

K-Type Thermocouple Measurement

ADS122U04 FP_TC_CJC_example_bas752.gif