EVALUATION KIT AVAILABLE Click here to ask about the production status of specific part numbers. MAX6675 Cold-Junction-Compensated K-Thermocouple- to-Digital Converter (0C to +1024C) General Description Features The MAX6675 performs cold-junction compensation and Direct Digital Conversion of Type -K Thermocouple digitizes the signal from a type-K thermocouple. The data Output is output in a 12-bit resolution, SPI-compatible, read-only Cold-Junction Compensation format. Simple SPI-Compatible Serial Interface This converter resolves temperatures to 0.25C, allows 12-Bit, 0.25C Resolution readings as high as +1024C, and exhibits thermocouple Open Thermocouple Detection accuracy of 8 LSBs for temperatures ranging from 0C to +700C. The MAX6675 is available in a small, 8-pin SO package. Ordering Information PART TEMP RANGE PIN-PACKAGE Applications Industrial MAX6675ISA -20C to +85C 8 SO Appliances HVAC Pin Configuration Typical Application Circuit Vcc TOP VIEW 0.1F GND 1 8 N.C. MAX6675 MICROCONTROLLER GND T- 2 7 SO 68HC11A8 MAX6675 SO MISO T+ 3 6 CS T+ SCK SCK V 4 5 SCK CC CS SSB T- SO 19-2235 Rev 3 6/21MAX6675 Cold-Junction-Compensated K-Thermocouple- to-Digital Converter (0C to +1024C) Absolute Maximum Ratings Supply Voltage (V to GND) ............................... -0.3V to +6V Storage Temperature Range ........................... -65C to +150C CC SO, SCK, CS, T-, T+ to GND .....................-0.3V to V + 0.3V Junction Temperature .................................................... +150C CC SO Current ....................................................................... 50mA SO Package ESD Protection (Human Body Model) .......................... 2000V Vapor Phase (60s) ....................................................+215C Continuous Power Dissipation (T = +70C) Infrared (15s) ..............................................................+220C A 8-Pin SO (derate 5.88mW/C above +70C) ............. 471mW Lead Temperature (soldering, 10s) ............................... +300C Operating Temperature Range .......................... -20C to +85C 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. Electrical Characteristics (V = +3.0V to +5.5V, T = -20C to +85C, unless otherwise noted. Typical values specified at +25C.) (Note 1) CC A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS V = +3.3V -5 +5 T = +700C, CC THERMOCOUPLE T = +25C (Note 2) V = +5V -6 +6 A CC V = +3.3V -8 +8 T = 0C to CC THERMOCOUPLE Temperature Error LSB +700C, T = +25C (Note 2) A V = +5V -9 +9 CC V = +3.3V -17 +17 T = +700C CC THERMOCOUPLE to +1000C, T = +25C (Note 2) V = +5V -19 +19 A CC Thermocouple Conversion 10.25 V/LSB Constant V = +3.3V -3.0 +3.0 Cold-Junction T = -20C to CC A C +85C (Note 2) Compensation Error V = +5V -3.0 +3.0 CC Resolution 0.25 C Thermocouple Input 60 kW Impedance Supply Voltage V 3.0 5.5 V CC Supply Current I 0.7 1.5 mA CC Power-On Reset Threshold V rising 1 2 2.5 V CC Power-On Reset Hysteresis 50 mV Conversion Time (Note 2) 0.17 0.22 s SERIAL INTERFACE 0.3 x Input Low Voltage V V IL V CC 0.7 x Input High Voltage V V IH V CC Input Leakage Current I V = GND or V 5 A LEAK IN CC Input Capacitance C 5 pF IN Maxim Integrated 2 www.maximintegrated.com