Description
The MAX6675 Thermocouple Module is a K-type thermocouple-to-digital converter designed for high-temperature measurement in appliances, HVAC systems, and industrial equipment. It performs cold-junction compensation, amplifies the thermocouple’s small voltage, and digitizes the signal internally, outputting temperature data via a simple SPI-compatible serial interface . The module resolves temperature to 0.25°C and can read up to +1024°C, with thermocouple accuracy specified at 8 LSBs over the 0°C to +700°C range .
A key practical detail: the MAX6675 is a converter IC, not a complete sensor. The K-type thermocouple itself is a separate component, and many breakout modules include a basic probe while others do not. The module also includes open-thermocouple detection: if the probe is disconnected, a fault bit is flagged in the data output, provided the T- terminal is grounded near the device .
Critical limitations: The MAX6675 measures only positive temperatures (0°C and above)—it cannot read below 0°C . It requires at least 220ms between readings because of its conversion time; polling faster returns stale or incorrect data . The device does not perform thermocouple linearization, so accuracy degrades at higher temperatures . For negative temperatures or improved precision, the MAX31855 is the recommended alternative .
Features
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Direct K-Type Thermocouple Interface: Integrates cold-junction compensation and digitization in one chip .
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12-Bit, 0.25°C Resolution: Fine-grained temperature readings .
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SPI-Compatible Read-Only Interface: Simple 3-wire connection to any microcontroller .
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Open-Thermocouple Detection: Fault bit flags a disconnected probe when T- is grounded .
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Wide Temperature Range: 0°C to +1024°C (accuracy specified to +700°C) .
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Low Power Consumption: Operates from 3.0V to 5.5V .
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Compact 8-Pin SO Package: Small footprint for space-constrained designs .
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Arduino Library Support: Widely available libraries simplify integration .
Technical Specifications
| Parameter | Specification |
|---|---|
| Sensor Type | K-type thermocouple-to-digital converter |
| Temperature Range | 0°C to +1024°C (accuracy specified 0–700°C) |
| Resolution | 12-bit, 0.25°C |
| Accuracy | 8 LSBs (0°C to +700°C) |
| Supply Voltage | 3.0V to 5.5V |
| Interface | SPI-compatible (read-only) |
| Conversion Time | 220ms maximum |
| Package | 8-pin SO (IC); breakout module varies |
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