MAX31856 Datasheet, PDF (1/30 Pages) Maxim Integrated Products – Precision Thermocouple to Digital Converter

MAX31856
EVALUATION KIT AVAILABLE
Precision Thermocouple to Digital Converter
with Linearization
General Description
The MAX31856 performs cold-junction compensation
and digitizes the signal from any type of thermocouple.
The output data is formatted in degrees Celsius. This
converter resolves temperatures to 0.0078125°C, allows
readings as high as +1800°C and as low as -210°C
(depending on thermocouple type), and exhibits thermo-
couple voltage measurement accuracy of ±0.15%. The
thermocouple inputs are protected against overvoltage
conditions up to ±45V.
A lookup table (LUT) stores linearity correction data for
several types of thermocouples (K, J, N, R, S, T, E, and
B). Line frequency filtering of 50Hz and 60Hz is included,
as is thermocouple fault detection. A SPI-compatible inter-
face allows selection of thermocouple type and setup of
the conversion and fault detection processes.
Applications
●● Temperature Controllers
●● Industrial Ovens, Furnaces, and Environmental
Chambers
●● Industrial Equipment
Ordering Information appears at end of data sheet.
Typical Application Circuit
Benefits and Features
●● Provides High-Accuracy Thermocouple Temperature
Readings
• Includes Automatic Linearization Correction for 8
Thermocouple Types
• ±0.15% (max, -20°C to +85°C) Thermocouple Full-
Scale and Linearity Error
• 19-Bit, 0.0078125°C Thermocouple Temperature
Resolution
●● Internal Cold-Junction Compensation Minimizes
System Components
• ±0.7°C (max, -20°C to +85°C) Cold-Junction
Accuracy
●● ±45V Input Protection Provides Robust System
Performance
●● Simplifies System Fault Management and
Troubleshooting
• Detects Open Thermocouples
• Over- and Undertemperature Fault Detection
●● 50Hz/60Hz Noise Rejection Filtering Improves
System Performance
●● 14-Pin TSSOP Package
AGND
DGND
0.01µF
0.1µF
0.01µF
3.3V
0.1µF
BIAS
T-
T+
AVDD
DNC
FAULT
SDI
MAX31856
SDO
SCK
CS
DRDY
DVDD
3.3V
0.1µF
TO MICROCONTROLLER
19-7534; Rev 0; 2/15