SBOS061C February   1997  – October 2024 XTR105

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings #GUID-80F0CD5F-C345-42B2-B6A9-580512790460/R_DESCRIPTION_LI1
    2. 5.2 Recommended Operating Conditions
    3. 5.3 Thermal Information
    4. 5.4 Electrical Characteristics
    5. 5.5 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Linearization
        1. 6.3.1.1 High-Resistance RTDs
      2. 6.3.2 Voltage Regulator
      3. 6.3.3 Open-Circuit Protection
      4. 6.3.4 Reverse-Voltage Protection
      5. 6.3.5 Surge Protection
    4. 6.4 Device Functional Modes
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 External Transistor
      2. 7.1.2 Loop Power Supply
      3. 7.1.3 2-Wire and 3-Wire RTD Connections
      4. 7.1.4 Radio Frequency Interference
      5. 7.1.5 Error Analysis
    2. 7.2 Typical Applications
    3. 7.3 Layout
      1. 7.3.1 Layout Guidelines
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • D|14
  • N|14
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6.3.1 Linearization

RTD temperature sensors are inherently (but predictably) nonlinear. With the addition of one or two external resistors, RLIN1 and RLIN2, compensation is possible for most of this nonlinearity by using the VLIN linearity correction feature of the XTR105. This results in a 40:1 improvement in linearity over the uncompensated output.

See Figure 7-1 for a typical 2-wire RTD application with linearization. Resistor RLIN1 provides positive feedback and controls linearity correction. RLIN1 is chosen according to the desired temperature range. An equation is given in Figure 7-1.

In 3-wire RTD connections, an additional resistor, RLIN2, is required. As with the 2-wire RTD application, RLIN1 provides positive feedback for linearization. RLIN2 provides an offset canceling current to compensate for wiring resistance encountered in remotely located RTDs. RLIN1 and RLIN2 are chosen such that the currents are equal. This makes the voltage drop in the wiring resistance to the RTD a common-mode signal that is rejected by the XTR105. The nearest standard 1% resistor values for RLIN1 and RLIN2 are adequate for most applications. Table 7-1 provides the 1% resistor values for a 3-wire Pt100 RTD connection.

If no linearity correction is desired, leave the VLIN pin open. With no linearization, RG = 2500m × VFS, where VFS = full-scale input range.