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RTD-to-Digital Converter

Complete Solution Provides a Digital Temperature Reading from an RTD with Fault Detection and Input Voltage Protection

Product Details

Key Features

Applications/Uses

Parametric specs for Temperature Sensors
Sensor Type Remote
# Channels One
Interface SPI
Functions RTD-to-Digital Converter
Thermistor-to-Digital Converter
Accuracy (±°C) 0.5
Parasite Pwr. No
Temp. Resolution (bits) 15
Oper. Temp. (°C) -40 to +125
Package/Pins SSOP/20
TQFN/20
Budgetary
Price (See Notes)
3.34
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Simplified Block Diagram

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Parameters

Parametric specs for Temperature Sensors
Sensor Type Remote
# Channels One
Interface SPI
Functions RTD-to-Digital Converter
Thermistor-to-Digital Converter
Accuracy (±°C) 0.5
Parasite Pwr. No
Temp. Resolution (bits) 15
Oper. Temp. (°C) -40 to +125
Package/Pins SSOP/20
TQFN/20
Budgetary
Price (See Notes)
3.34

Key Features

  • Integration Lowers System Cost, Simplifies Design Efforts, and Reduces Design Cycle Time
    • Simple Conversion of Platinum RTD Resistance to Digital Value
    • Handles 100Ω to 1kΩ (at 0°C) Platinum RTDs (PT100 to PT1000)
    • Compatible with 2-, 3-, and 4-Wire Sensor Connections
    • SPI-Compatible Interface
    • 20-Pin TQFN and SSOP Packages
  • High Accuracy Facilitates Meeting Error Budgets
    • 15-Bit ADC Resolution; Nominal Temperature Resolution 0.03125°C (Varies Due to RTD Nonlinearity)
    • Total Accuracy Over All Operating Conditions: 0.5°C (0.05% of Full Scale) max
    • Fully Differential VREF Inputs
    • 21ms (max) Conversion Time
  • Integrated Fault Detection Increases System Reliability
    • ±45V Input Protection
    • Fault Detection (Open RTD Element, RTD Shorted to Out-of-Range Voltage, or Short Across RTD Element)

Applications/Uses

  • Industrial Equipment
  • Instrumentation
  • Medical Equipment

Description

The MAX31865 is an easy-to-use resistance-to-digital converter optimized for platinum resistance temperature detectors (RTDs). An external resistor sets the sensitivity for the RTD being used and a precision delta-sigma ADC converts the ratio of the RTD resistance to the reference resistance into digital form. The MAX31865's inputs are protected against overvoltage faults as large as ±45V. Programmable detection of RTD and cable open and short conditions is included.

Design Solution: Achieve High-Accuracy Temperature Measurement in Your Precision Designs ›


How to Measure Temperature Using RTDs and the MAX31865EVKIT

Simplified Block Diagram

MAX31865: Block Diagram MAX31865: Block Diagram Zoom icon

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .