MAX31855NASA+T Maxim Integrated, MAX31855NASA+T Datasheet

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MAX31855NASA+T

Manufacturer Part Number
MAX31855NASA+T
Description
Data Conversion ICs - Various Thermocouple To Digital Converter
Manufacturer
Maxim Integrated
Series
MAX31855r
Datasheet

Specifications of MAX31855NASA+T

Rohs
yes
Part # Aliases
90-31855+NTR
Pin Configurations appear at end of data sheet.
Functional Diagrams continued at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
The MAX31855 performs cold-junction compensation
and digitizes the signal from a K-, J-, N-, T-, S-, R-, or
E-type thermocouple. The data is output in a signed
14-bit, SPI-compatible, read-only format. This converter
resolves temperatures to 0.25NC, allows readings as high
as +1800NC and as low as -270NC, and exhibits thermo-
couple accuracy of ±2NC for temperatures ranging from
-200NC to +700NC for K-type thermocouples. For full
range accuracies and other thermocouple types, see the
Thermal Characteristics
Industrial
Appliances
HVAC
Automotive
Functional Diagrams
specifications.
General Description
0.1µF
Applications
Thermocouple-to-Digital Converter
V
GND
T+
T-
CC
MAX31855
Cold-Junction Compensated
SCK
SO
CS
S Cold-Junction Compensation
S 14-Bit, 0.25NC Resolution
S Versions Available for K-, J-, N-, T-, S-, R-, and
S Simple SPI-Compatible Interface (Read-Only)
S Detects Thermocouple Shorts to GND or V
S Detects Open Thermocouple
Ordering Information
For related parts and recommended products to use with this part,
refer to:
E-Type Thermocouples (see
www.maxim-ic.com/MAX31855.related
MISO
SCK
SS
Typical Application Circuit
MICROCONTROLLER
appears at end of data sheet.
MAX31855
Table
1)
19-5793; Rev 2; 2/12
Features
CC

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MAX31855NASA+T Summary of contents

Page 1

... Functional Diagrams Pin Configurations appear at end of data sheet. Functional Diagrams continued at end of data sheet. UCSP is a trademark of Maxim Integrated Products, Inc. For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com. Cold-Junction Compensated Thermocouple-to-Digital Converter S Cold-Junction Compensation S 14-Bit, 0 ...

Page 2

... Thermocouple Input Bias Current Power-Supply Rejection Power-On Reset Voltage Threshold Power-On Reset Voltage Hysteresis Output High Voltage Output Low Voltage Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter Operating Temperature Range ........................ -40NC to +125NC + 0.3V) Junction Temperature .....................................................+150NC CC Storage Temperature Range .......................... -65NC to +150NC Lead Temperature (soldering, 10s) ................................+300NC Soldering Temperature (reflow) ...

Page 3

... Error (76.373FV/NC nominal sensitivity) (Note 4) MAX31855R Thermocouple Temperature Gain and Offset Error (10.506FV/NC nominal sensitivity) (Note 4) MAX31855S Thermocouple Temperature Gain and Offset Error (9.587FV/NC nominal sensitivity) (Note 4) Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter SYMBOL CONDITIONS T = -200NC to +700NC, THERMOCOUPLE T = -20NC to +85NC (Note 3) ...

Page 4

... Therefore, the t greater than V to guarantee a valid thermocouple temperature conversion result. CCMIN Note 7: For all pins except T+ and T- (see the Thermocouple Input Bias Current parameter in the table). Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter SYMBOL CONDITIONS T ...

Page 5

... CS SCK SO D31 Figure 1. Serial-Interface Protocol t CSS CS SCK D31 Figure 2. Serial-Interface Timing Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter MAX31855 Serial-Interface Diagrams ...

Page 6

... TEMPERATURE (°C) ADC ACCURACY vs. ADC INPUT VOLTAGE ACROSS TEMPERATURE 0.3 AT -40°C 0.2 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5 -0 3. ADC INPUT VOLTAGE (mV) Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter Typical Operating Characteristics 100 120 AT +85°C AT +25° MAX31855 INTERNAL TEMPERATURE SENSOR ACCURACY 0 3.3V CC ...

Page 7

... Pin Configuration TOP VIEW + GND MAX31855 Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter PIN DNC SCK COLD-JUNCTION MAX31855 COMPENSATION S4 S1 FAULT S2 DETECTION REFERENCE S3 VOLTAGE MAX31855 Pin Description NAME FUNCTION GND Ground Thermocouple Input ...

Page 8

... Copper E Constantan Chromel Platinum Platinum/Rhodium R Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter for the difference between the thermocouple cold- junction side (device ambient temperature) and a 0NC virtual reference. For a K-type thermocouple, the volt- age changes by about 41FV/NC, which approximates the thermocouple characteristic with the following linear ...

Page 9

... S3) and the connection to the ADC (switch S4) are closed. This allows the ADC to process the voltage detected across the T+ and T- terminals. Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter During fault detection, the connections from the exter- nal thermocouple and cold-junction compensation cir- cuit to the ADC are opened (switches S4 and S5) ...

Page 10

... OC Fault Table 4. Thermocouple Temperature Data Format TEMPERATURE (NC) +1600.00 +1000.00 +100.75 +25.00 0.00 -0.25 -1.00 -250.00 Note: The practical temperature ranges vary with the thermocouple type. Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter FAULT 12-BIT INTERNAL TEMPERATURE RES BIT D17 D16 D15 D14 MSB - Reserved ...

Page 11

... Use a large ground plane to improve the device’s temperature measurement accuracy. Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter The thermocouple system’s accuracy can also be improved by following these precautions: • ...

Page 12

... PART MAX31855KASA+ MAX31855KASA+T MAX31855JASA+ MAX31855JASA+T MAX31855NASA+ MAX31855NASA+T MAX31855SASA+ MAX31855SASA+T MAX31855TASA+ MAX31855TASA+T MAX31855EASA+ MAX31855EASA+T MAX31855RASA+ MAX31855RASA+T Note: All devices are specified over the -40°C to +125°C operating temperature range. +Denotes a lead(Pb)-free/RoHS-compliant package Tape and reel. For the latest package outline information and land patterns (footprints www.maxim-ic.com/packages. Note that a “+”, “#”, or “ ...

Page 13

... Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000 © Maxim Integrated Cold-Junction Compensated Thermocouple-to-Digital Converter DESCRIPTION The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc. MAX31855 Revision History PAGES CHANGED — ...

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