The MAX6675 is a precision thermocouple-to-digital converter IC designed for accurate temperature measurements using K-type thermocouples. Packaged in an 8-pin SOIC (Small Outline Integrated Circuit), it integrates essential features such as cold-junction compensation and a 12-bit analog-to-digital converter (ADC), facilitating seamless interfacing with microcontrollers via the SPI (Serial Peripheral Interface) protocol.

The MAX6675 digitizes the small voltage generated by a K-type thermocouple and provides a digital output corresponding to the measured temperature. Its integrated cold-junction compensation ensures that temperature readings are accurate regardless of ambient temperature changes at the connection point. The device communicates via a simple SPI interface, making it compatible with a wide range of microcontrollers.

Features :

• Thermocouple Compatibility: Supports K-type thermocouples.
• Temperature Measurement Range: 0°C to +1024°C.
• Resolution: 12-bit, providing 0.25°C temperature resolution.
• Accuracy: ±2°C for temperatures ranging from 0°C to +700°C .
• Cold-Junction Compensation: Integrated on-chip compensation ensures accurate readings by accounting for ambient temperature variations.
• Open Thermocouple Detection: Detects and signals if the thermocouple is disconnected or broken.
• SPI Interface: Simple, read-only SPI-compatible serial interface for easy integration with microcontrollers.

Specifications :

• Operating Voltage: 3.0V to 5.5V.
• Operating Temperature Range: -20°C to +85°C.
• Package Type: 8-pin SOIC .
• Pin Configuration
  • T+: Positive input from the thermocouple.
  • T-: Negative input from the thermocouple.
  • GND: Ground reference.
  • VCC: Supply voltage input (3.0V to 5.5V).
  • SCK: Serial Clock Input for SPI communication.
  • CS: Chip Select input; active low.
  • SO: Serial Data Output; transmits temperature data.
  • NC: No internal connection; typically left unconnected.

Applications :

• Industrial Process Control: Monitoring and controlling temperatures in manufacturing processes.
• HVAC Systems: Temperature regulation in heating, ventilation, and air conditioning systems.
• Appliances: Temperature sensing in ovens, toasters, and other household appliances.
• Laboratory Equipment: Precise temperature measurements in scientific instruments.

Datasheet : MAX6675 Datasheet