MAX6675

Cold-Junction-Compensated K-Thermocoupleto-Digital Converter (0°C to +1024°C)

Manufacturer

adi

Overview

Part 1: Markdown Summary

Part: MAX6675

Type: Cold-Junction-Compensated K-Thermocouple-to-Digital Converter

Key Specs:

Temperature Range: 0°C to +1024°C
Resolution: 12-bit, 0.25°C
Thermocouple Accuracy: 8 LSBs (for 0°C to +700°C)
Supply Voltage: +3.0V to +5.5V
Supply Current: 0.7 mA (typ), 1.5 mA (max)
Conversion Time: 0.17 s (typ), 0.22 s (max)
Serial Clock Frequency: 4.3 MHz (max)

Features:

Direct Digital Conversion of Type -K Thermocouple Output
Cold-Junction Compensation
Simple SPI-Compatible Serial Interface
12-Bit, 0.25°C Resolution
Open Thermocouple Detection

Applications:

Industrial
Appliances
HVAC

Package:

8-pin SO: dimensions not specified

Features

Direct Digital Conversion of Type -K Thermocouple Output
Cold-Junction Compensation
Simple SPI-Compatible Serial Interface
12-Bit, 0.25°C Resolution
Open Thermocouple Detection

Applications

Industrial
Appliances
HVAC

Features

Direct Digital Conversion of Type -K Thermocouple Output
Cold-Junction Compensation
Simple SPI-Compatible Serial Interface
12-Bit, 0.25°C Resolution
Open Thermocouple Detection

Pin Configuration

Electrical Characteristics

(VCC = +3.0V to +5.5V, TA = -20°C to +85°C, unless otherwise noted. Typical values specified at +25°C.) (Note 1)

PARAMETER	SYMBOL	CONDITIONS				TYP	MAX	UNITS
		VCC = +3.3V TTHERMOCOUPLE = +700°C,					+5
		TA = +25°C (Note 2)		VCC = +5V	-6		+6
		TTHERMOCOUPLE	= 0°C to	VCC = +3.3V	-8		+8
Temperature Error		+700°C, TA	= +25°C (Note 2) VCC = +5V		-9		+9	LSB
		TTHERMOCOUPLE	= +700°C	VCC = +3.3V	-17		+17
		to +1000°C, TA	= +25°C (Note 2)	VCC = +5V	-19		+19
Thermocouple Conversion Constant						10.25		µV/LSB
Cold-Junction		TA = - 2 0 ° C t o	VCC = +3.3V		-3.0		+3.0
Compensation Error		+85°C (Note 2)	VCC = +5V		-3.0		+3.0	°C
Resolution						0.25		°C
Thermocouple Input Impedance						60		kW
Supply Voltage	VCC				3.0		5.5	V
Supply Current	ICC					0.7	1.5	mA
Power-On Reset Threshold		VCC rising			1	2	2.5	V
Power-On Reset Hysteresis						50		mV
Conversion Time		(Note 2)				0.17	0.22	s
SERIAL INTERFACE
Input Low Voltage	VIL						0.3 x VCC	V
Input High Voltage	VIH				0.7 x VCC			V
Input Leakage Current	ILEAK	VIN = GND or VCC					±5	µA
Input Capacitance	CIN					5		pF

Absolute Maximum Ratings

Supply Voltage (VCC to GND)0.3V to +6V	Storage Temperature Range65°C to +150°C
SO, SCK, CS, T-, T+ to GND0.3V to VCC + 0.3V	Junction Temperature +150°C
SO Current 50mA	SO Package
ESD Protection (Human Body Model) ±2000V	Vapor Phase (60s)+215°C
Continuous Power Dissipation (TA = +70°C)	Infrared (15s)+220°C
8-Pin SO (derate 5.88mW/°C above +70°C) 471mW	Lead Temperature (soldering, 10s) +300°C
Operating Temperature Range20°C to +85°C
Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

Thermal Information

Self-heating degrades the temperature measurement accuracy of the MAX6675 in some applications. The magnitude of the temperature errors depends on the thermal conductivity of the MAX6675 package, the mounting technique, and the effects of airflow. Use a large ground plane to improve the temperature measurement accuracy of the MAX6675.

The accuracy of a thermocouple system can also be improved by following these precautions:

Use the largest wire possible that does not shunt heat away from the measurement area.
If small wire is required, use it only in the region of the measurement and use extension wire for the region with no temperature gradient.
Avoid mechanical stress and vibration, which could strain the wires.
When using long thermocouple wires, use a twistedpair extension wire.
Avoid steep temperature gradients.
Try to use the thermocouple wire well within its temperature rating.
Use the proper sheathing material in hostile environments to protect the thermocouple wire.
Use extension wire only at low temperatures and only in regions of small gradients.
Keep an event log and a continuous record of thermocouple resistance.

Data on this page is extracted from publicly available manufacturer datasheets using automated tools including AI. It may contain errors or omissions. Always verify specifications against the official manufacturer datasheet before making design or purchasing decisions. See our Terms of Service. Rights holders can submit a takedown request.

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