MAX31850/MAX31851

Cold-Junction Compensated, 1-Wire

Thermocouple-to-Digital Converters

General Description

The MAX31850/MAX31851 cold-junction compensat-

cold-junction compensation and digitize the signal from

a K-, J-, N-, T-, S-, R-, or E-type thermocouple. The con-

verters resolve temperatures to 0.25NC, allow readings

as high as +1768NC and as low as -270NC, and exhibit

thermocouple accuracy of 8 LSBs (2NC) for temperatures

ranging from -200NC to +700NC.

Communication with the master microcontroller is over a

1-Wire bus that by definition requires only one data line

(and ground) for communication. Operating power can

be obtained directly from the data line (“parasite power”),

eliminating the need for an external power supply.

Each device has a unique 64-bit serial code, which

allows multiple units to function on the same 1-Wire bus.

Therefore, it is simple to use one microcontroller (the

master device) to monitor temperature from many ther-

mocouples distributed over a large area.

Four location address inputs simplify mapping of

individual units to specific locations.

Features

S

Cold-Junction Compensation

S

14-Bit, 0.25NC Resolution

S

Versions Available for K-, J-, N-, T-, S-, R-, and

E-Type Thermocouples (see Table 1)

S

1-Wire Interface (Read-Only); Power Can Be

Obtained from Interface (Parasite-Powered Mode)

S

S

Detects Open Thermocouple

Applications

Industrial

Appliances

HVAC

Medical

Block Diagram

19-6725; Rev 0; 6/13

Ordering Information appears at end of data sheet.

1-Wire is a registered trademark of Maxim Integrated Products, Inc.

For related parts and recommended products to use with this part, refer to: www.maximintegrated.com/MAX31850.related

EVALUATION KIT AVAILABLE

MAX31850

MAX31851

64-BIT ROM

AND

1-Wire PORT

ADC

PARASITE-

POWER

CIRCUIT

DQ

GND

MEMORY

CONTROL LOGIC

COLD-JUCTION

COMPENSATION

FAULT

DETECTION

REFERENCE

VOLTAGE

POWER-

SUPPLY

SENSE

ADDRESS PIN INPUT

AD0 AD1 AD2 AD3

SCRATCHPAD

S5

S1

S3

T+

T-

S2

S4

For pricing, delivery, and ordering information, please contact Maxim Direct at

1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.