MAX31865
RTD-to-Digital Converter
Complete Solution Provides a Digital Temperature Reading from an RTD with Fault Detection and Input Voltage Protection
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Key Features
Applications/Uses
| 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 |
Simplified Block Diagram
Choosing the Best Type of Temperature Sensor
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Parameters
| 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 ›
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Filtered SearchOur dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .
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