MAX31865 RTD-to-Digital Converter

Product Highlights > MAX31865 RTD-to-Digital Converter

            MAX31865 RTD-to-Digital Converter
                    Analog Devices' single-chip, RTD-to-Digital converter reduces costs by 50%
    

The Analog Devices 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, and a precision delta-sigma ADC converts the ratio of the RTD resistance to the reference resistance into digital form. The MAX31865 inputs resist overvoltage faults as large as ±50 V. Programmable detection of RTD open, cable open, and short conditions is included.

The MAX31865 simply and elegantly solves the common industrial design problem of digitizing a platinum RTD (such as a PT100 or PT1000) resistance, protects against ±50 V input overvoltages, and detects sensor and cable faults. In addition, the device simplifies resistance measurement by eliminating the precisely matched current sources used for 3-wire sensor connections in conventional designs. The built-in overvoltage protection (OVP) also eliminates the need for external protection circuitry, which lowers cost, reduces board space, and increases factory uptime.

Features
Simple conversion of platinum RTD resistance to digital value Handles 100 Ω to 1 kΩ (at 0°C) platinum RTDs (PT100 to PT1000) Compatible with 2-, 3-, and 4-wire sensor connections Conversion time: 21 ms max 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		±50 V input protection Fully differential V_REF inputs Fault detection (open RTD element, RTD shorted to out-of-range voltage, or short across RTD element) SPI-compatible interface 20-pin TQFN package