MAX31855JASA+T - Maxim

AVAILABLE

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

General Description

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 specifications.

Applications

Industrial

Appliances

HVAC

Automotive

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 Simple SPI-Compatible Interface (Read-Only)

S Detects Thermocouple Shorts to GND or VCC

S Detects Open Thermocouple

Typical Application Circuit

19-5793; Rev 2; 2/12

For related parts and recommended products to use with this part,

refer to: www.maxim-ic.com/MAX31855.related

Ordering Information appears at end of data sheet.

VCC

GND

T+

T-

SCK

MICROCONTROLLER

MISO

SCK

0.1µF

MAX31855

Cold-Junction Compensated

Thermocouple-to-Digital Converter

Supply Voltage Range (VCC to GND) .................. -0.3V to +4.0V

All Other Pins ............................................ -0.3V to (VCC + 0.3V)

Continuous Power Dissipation (TA = +70NC)

SO (derate 5.9mW/NC above +70NC) ....................... 470.6mW

ESD Protection (All Pins, Human Body Model) ...................±2kV

Operating Temperature Range ........................ -40NC to +125NC

Junction Temperature .....................................................+150NC

Storage Temperature Range .......................... -65NC to +150NC

Lead Temperature (soldering, 10s) ................................+300NC

Soldering Temperature (reflow) .....................................+260NC

Junction-to-Ambient Thermal Resistance (BJA) ........170NC/W

Junction-to-Case Thermal Resistance (BJC) ...............40NC/W

ABSOLUTE MAXIMUM RATINGS

Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-

layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional opera-

tion 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.

PACKAGE THERMAL CHARACTERISTICS (Note 1)

RECOMMENDED OPERATING CONDITIONS

(TA = -40NC to +125NC, unless otherwise noted.)

DC ELECTRICAL CHARACTERISTICS

(3.0V P VCC P 3.6V, TA = -40NC to +125NC, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Power-Supply Voltage VCC (Note 2) 3.0 3.3 3.6 V

Input Logic 0 VIL -0.3 +0.8 V

Input Logic 1 VIH 2.1 VCC +

0.3 V

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Power-Supply Current ICC 900 1500 FA

Thermocouple Input Bias Current TA = -40NC to +125NC, 100mV across the

thermocouple inputs -100 +100 nA

Power-Supply Rejection -0.3 NC/V

Power-On Reset Voltage

Threshold VPOR (Note 3) 2 2.5 V

Power-On Reset Voltage

Hysteresis 0.2 V

Output High Voltage VOH IOUT = -1.6mA VCC -

0.4 V

Output Low Voltage VOL IOUT = 1.6mA 0.4 V

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

THERMAL CHARACTERISTICS

(3.0V P VCC P 3.6V, TA = -40NC to +125NC, unless otherwise noted.) (Note 4)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

MAX31855K Thermocouple

Temperature Gain and Offset

Error (41.276FV/NC nominal

sensitivity) (Note 4)

TTHERMOCOUPLE = -200NC to +700NC,

TA = -20NC to +85NC (Note 3) -2 +2

TTHERMOCOUPLE = +700NC to +1350NC,

TA = -20NC to +85NC (Note 3) -4 +4

TTHERMOCOUPLE = -270NC to +1372NC,

TA = -40NC to +125NC (Note 3) -6 +6

MAX31855J Thermocouple

Temperature Gain and Offset

Error (57.953FV/NC nominal

sensitivity) (Note 4)

TTHERMOCOUPLE = -210NC to +750NC,

TA = -20NC to +85NC (Note 3) -2 +2

TTHERMOCOUPLE = -210NC to +1200NC,

TA = -40NC to +125NC (Note 3) -4 +4

MAX31855N Thermocouple

Temperature Gain and Offset

Error (36.256FV/NC nominal

sensitivity) (Note 4)

TTHERMOCOUPLE = -200NC to +700NC,

TA = -20NC to +85NC (Note 3) -2 +2

TTHERMOCOUPLE = +700NC to +1300NC,

TA = -20NC to +85NC (Note 3) -4 +4

TTHERMOCOUPLE = -270NC to +1300NC,

TA = -40NC to +125NC (Note 3) -6 +6

MAX31855T Thermocouple

Temperature Gain and Offset

Error (52.18FV/NC nominal

sensitivity) (Note 4)

TTHERMOCOUPLE = -270NC to +400NC,

TA = -20NC to +85NC (Note 3) -2 +2

TTHERMOCOUPLE = -270NC to +400NC,

TA = -40NC to +125NC (Note 3) -4 +4

MAX31855E Thermocouple

Temperature Gain and Offset

Error (76.373FV/NC nominal

sensitivity) (Note 4)

TTHERMOCOUPLE = -200NC to +700NC,

TA = -20NC to +85NC (Note 3) -2 +2

TTHERMOCOUPLE = +700NC to +1000NC,

TA = -20NC to +85NC (Note 3) -3 +3

TTHERMOCOUPLE = -270NC to +1000NC,

TA = -40NC to +125NC (Note 3) -5 +5

MAX31855R Thermocouple

Temperature Gain and Offset

Error (10.506FV/NC nominal

sensitivity) (Note 4)

TTHERMOCOUPLE = -50NC to +700NC,

TA = -20NC to +85NC (Note 3) -2 +2

TTHERMOCOUPLE = +700NC to +1768NC,

TA = -20NC to +85NC (Note 3) -4 +4

TTHERMOCOUPLE = -50NC to +1768NC,

TA = -40NC to +125NC (Note 3) -6 +6

MAX31855S Thermocouple

Temperature Gain and Offset

Error (9.587FV/NC nominal

sensitivity) (Note 4)

TTHERMOCOUPLE = -50NC to +700NC,

TA = -20NC to +85NC (Note 3) -2 +2

TTHERMOCOUPLE = +700NC to +1768NC,

TA = -20NC to +85NC (Note 3) -4 +4

TTHERMOCOUPLE = -50NC to +1768NC,

TA = -40NC to +125NC (Note 3) -6 +6

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

Note 2: All voltages are referenced to GND. Currents entering the IC are specified positive, and currents exiting the IC are negative.

Note 3: Guaranteed by design; not production tested.

Note 4: Not including cold-junction temperature error or thermocouple nonlinearity.

Note 5: Specification is 100% tested at TA = +25NC. Specification limits over temperature (TA = TMIN to TMAX) are guaranteed by

design and characterization; not production tested.

Note 6: Because the thermocouple temperature conversions begin at VPOR, depending on VCC slew rates, the first thermocouple

temperature conversion may not produce an accurate result. Therefore, the tCONV_PU specification is required after VCC is

greater than VCCMIN to guarantee a valid thermocouple temperature conversion result.

Note 7: For all pins except T+ and T- (see the Thermocouple Input Bias Current parameter in the DC Electrical Characteristics

table).

SERIAL-INTERFACE TIMING CHARACTERISTICS

(See Figure 1 and Figure 2.)

THERMAL CHARACTERISTICS (continued)

(3.0V P VCC P 3.6V, TA = -40NC to +125NC, unless otherwise noted.) (Note 4)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Input Leakage Current ILEAK (Note 7) -1 +1 µA

Input Capacitance CIN 8 pF

Serial-Clock Frequency fSCL 5 MHz

SCK Pulse-High Width tCH 100 ns

SCK Pulse-Low Width tCL 100 ns

SCK Rise and Fall Time 200 ns

CS Fall to SCK Rise tCSS 100 ns

SCK to CS Hold 100 ns

CS Fall to Output Enable tDV 100 ns

CS Rise to Output Disable tTR 40 ns

SCK Fall to Output Data Valid tDO 40 ns

CS Inactive Time (Note 3) 200 ns

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Thermocouple Temperature Data

Resolution 0.25 NC

Internal Cold-Junction

Temperature Error

TA = -20NC to +85NC (Note 3) -2 +2 NC

TA = -40NC to +125NC (Note 3) -3 +3

Cold-Junction Temperature Data

Resolution TA = -40NC to +125NC0.0625 NC

Temperature Conversion Time

(Thermocouple, Cold Junction,

Fault Detection)

tCONV (Note 5) 70 100 ms

Thermocouple Conversion

Power-Up Time tCONV_PU (Note 6) 200 ms

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

Serial-Interface Diagrams

Figure 1. Serial-Interface Protocol

Figure 2. Serial-Interface Timing

SCK

SO D31 D8 D7 D6 D5 D4 D3 D2 D1

D31 D0D1D2D3

SCK

tDV

tCSS

tDO

tTR

tCH tCL

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

Typical Operating Characteristics

(VCC = +3.3V, TA = +25NC, unless otherwise noted.)

ADC ACCURACY vs. ADC INPUT VOLTAGE

ACROSS VCC

MAX31855 toc04

ADC INPUT VOLTAGE (mV)

ADC ACCURACY (°C)

4020

-0.9

-0.8

-0.7

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

-1.0

VCC = 3.6V

VCC = 3.3V

VCC = 3.0V

INTERNAL TEMPERATURE = +25°C

ADC ACCURACY vs. ADC INPUT VOLTAGE

ACROSS TEMPERATURE

MAX31855 toc03

ADC INPUT VOLTAGE (mV)

ADC ACCURACY (°C)

4020

-0.6

-0.5

-0.4

-0.3

-0.2

-0.1

0.1

0.2

0.3

-0.7

AT -40°C

VCC = 3.3V

AT +85°C

AT +25°C

INTERNAL TEMPERATURE SENSOR

ACCURACY

MAX31855 toc02

TEMPERATURE (°C)

MEASUREMENT ERROR (°C)

806020 400-20

-0.1

0.1

0.2

0.3

0.4

0.5

0.6

0.7

-0.2

-40 100

VCC = 3.3V

NOTE: THIS DATA WAS TAKEN

IN PRECISION BATH SO HIGH

TEMPERATURE LIMIT IS 90°C

SUPPLY CURRENT vs. TEMPERATURE

MAX31855 toc01

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

100 120806040200-20

0.2

0.4

0.6

0.8

1.0

1.2

1.4

-40

VCC = 3.6V

VCC = 3.3V

VCC = 3.0V

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

Pin Description

Pin Configuration

Block Diagram

PIN NAME FUNCTION

1 GND Ground

2 T- Thermocouple Input. See Table 1. Do

not connect to GND.

3 T+ Thermocouple Input. See Table 1.

4 VCC Power-Supply Voltage

5 SCK Serial-Clock Input

6CS Active-Low Chip Select. Set CS low to

enable the serial interface.

7 SO Serial-Data Output

8 DNC Do Not Connect

SCKVCC

DNC

SOT-

T+

GND

TOP VIEW

MAX31855

ADC

DIGITAL

CONTROL

COLD-JUNCTION

COMPENSATION

FAULT

DETECTION

REFERENCE

VOLTAGE

S5 SCK

VCC

GND

T+

T-

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

Table 1. Thermocouple Wire Connections and Nominal Sensitivities

Detailed Description

The MAX31855 is a sophisticated thermocouple-to-

digital converter with a built-in 14-bit analog-to-digital

converter (ADC). The device also contains cold-junction

compensation sensing and correction, a digital control-

ler, an SPI-compatible interface, and associated control

logic. The device is designed to work in conjunction

with an external microcontroller (FC) in thermostatic,

process-control, or monitoring applications. The device

is available in several versions, each optimized and

trimmed for a specific thermocouple type (K, J, N, T, S,

R, or E.). The thermocouple type is indicated in the suffix

of the part number (e.g., MAX31855K). See the Ordering

Information table for all options.

Temperature Conversion

The device includes signal-conditioning hardware to

convert the thermocouple’s signal into a voltage com-

patible with the input channels of the ADC. The T+ and

T- inputs connect to internal circuitry that reduces the

introduction of noise errors from the thermocouple wires.

Before converting the thermoelectric voltages into equiv-

alent temperature values, it is necessary to compensate

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

equation:

VOUT = (41.276FV/NC) x (TR - TAMB)

where VOUT is the thermocouple output voltage (FV), TR

is the temperature of the remote thermocouple junction

(NC), and TAMB is the temperature of the device (NC).

Other thermocouple types use a similar straight-line

approximation but with different gain terms. Note that the

MAX31855 assumes a linear relationship between tem-

perature and voltage. Because all thermocouples exhibit

some level of nonlinearity, apply appropriate correction

to the device’s output data.

Cold-Junction Compensation

The function of the thermocouple is to sense a difference

in temperature between two ends of the thermocouple

wires. The thermocouple’s “hot” junction can be read

across the operating temperature range (Table 1). The

reference junction, or “cold” end (which should be at

TYPE T- WIRE T+ WIRE TEMP RANGE (°C) SENSITIVITY (µV/°C)

COLD-JUNCTION

SENSITIVITY (µV/°C)

(0NC TO +70NC)

KAlumel Chromel -270 to +1372 41.276

(0NC to +1000NC) 40.73

JConstantan Iron -210 to +1200 57.953

(0NC to +750NC) 52.136

NNisil Nicrosil -270 to + 1300 36.256

(0NC to +1000NC) 27.171

SPlatinum Platinum/Rhodium +50 to +1768 9.587

(0NC to +1000NC) 6.181

TConstantan Copper -270 to +400 52.18

(0NC to +400NC) 41.56

EConstantan Chromel -270 to +1000 76.373

(0NC to +1000NC) 44.123

RPlatinum Platinum/Rhodium -50 to +1768 10.506

(0NC to +1000NC) 6.158

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

the same temperature as the board on which the device

is mounted) can range from -55NC to +125NC. While the

temperature at the cold end fluctuates, the device con-

tinues to accurately sense the temperature difference at

the opposite end.

The device senses and corrects for the changes in

the reference junction temperature with cold-junction

compensation. It does this by first measuring its internal

die temperature, which should be held at the same tem-

perature as the reference junction. It then measures the

voltage from the thermocouple’s output at the reference

junction and converts this to the noncompensated ther-

mocouple temperature value. This value is then added

to the device’s die temperature to calculate the thermo-

couple’s “hot junction” temperature. Note that the “hot

junction” temperature can be lower than the cold junction

(or reference junction) temperature.

Optimal performance from the device is achieved when

the thermocouple cold junction and the device are at

the same temperature. Avoid placing heat-generating

devices or components near the MAX31855 because this

could produce cold-junction-related errors.

Conversion Functions

During the conversion time, tCONV, three functions are

performed: the temperature conversion of the internal

cold-junction temperature, the temperature conversion of

the external thermocouple, and the detection of thermo-

couple faults.

When executing the temperature conversion for the inter-

nal cold-junction compensation circuit, the connection to

signal from the external thermocouple is opened (switch

S4) and the connection to the cold-junction compensa-

tion circuit is closed (switch S5). The internal T- reference

to ground is still maintained (switch S3 is closed) and

the connections to the fault-detection circuit are open

(switches S1 and S2).

When executing the temperature conversion of the

external thermocouple, the connections to the internal

fault-detection circuit are opened (switches S1 and S2 in

the Block Diagram) and the switch connecting the cold-

junction compensation circuit is opened (switch S5). The

internal ground reference connection (switch 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.

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). The

internal ground reference on T- is also opened (switch

S3). The connections to the internal fault-detection cir-

cuit are closed (switch S1 and S2). The fault-detection

circuit tests for shorted connections to VCC or GND on

the T+ and T- inputs, as well as looking for an open

thermocouple condition. Bits D0, D1, and D2 of the

output data are normally low. Bit D2 goes high to indi-

cate a thermocouple short to VCC, bit D1 goes high to

indicate a thermocouple short to GND, and bit D0 goes

high to indicate a thermocouple open circuit. If any of

these conditions exists, bit D16 of the SO output data,

which is normally low, also goes high to indicate that a

fault has occurred.

Serial Interface

The Typical Application Circuit shows the device inter-

faced with a microcontroller. In this example, the device

processes the reading from the thermocouple and

transmits the data through a serial interface. Drive CS

low and apply a clock signal at SCK to read the results

at SO. Conversions are always being performed in the

background. The fault and temperature data are only be

updated when CS is high.

Drive CS low to output the first bit on the SO pin. A

complete serial-interface read of the cold-junction com-

pensated thermocouple temperature requires 14 clock

cycles. Thirty-two clock cycles are required to read both

the thermocouple and reference junction temperatures

(Table 2 and Table 3.) The first bit, D31, is the thermo-

couple temperature sign bit, and is presented to the SO

pin within tDV of the falling edge of CS. Bits D[30:18]

contain the converted temperature in the order of MSB

to LSB, and are presented to the SO pin within tD0 of the

falling edge of SCK. Bit D16 is normally low and goes

high when the thermocouple input is open or shorted to

GND or VCC. The reference junction temperature data

begins with D15. CS can be taken high at any point while

clocking out conversion data. If T+ and T- are uncon-

nected, the thermocouple temperature sign bit (D31) is

0, and the remainder of the thermocouple temperature

value (D[30:18]) is 1.

Figure 1 and Figure 2 show the serial-interface timing

and order. Table 2 and Table 3 show the SO output bit

weights and functions.

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

Table 3. Memory Map—Descriptions

Table 4. Thermocouple Temperature Data

Format

Table 5. Reference Junction Temperature

Data Format

Note: The practical temperature ranges vary with the

thermocouple type.

Table 2. Memory Map—Bit Weights and Functions

BIT NAME DESCRIPTION

D[31:18] 14-Bit Thermocouple

Temperature Data These bits contain the signed 14-bit thermocouple temperature value. See Table 4.

D17 Reserved This bit always reads 0.

D16 Fault This bit reads at 1 when any of the SCV, SCG, or OC faults are active. Default value

is 0.

D[15:4] 12-Bit Internal Temperature

Data

These bits contain the signed 12-bit value of the reference junction temperature.

See Table 5.

D3 Reserved This bit always reads 0.

D2 SCV Fault This bit is a 1 when the thermocouple is short-circuited to VCC. Default value is 0.

D1 SCG Fault This bit is a 1 when the thermocouple is short-circuited to GND. Default value is 0.

D0 OC Fault This bit is a 1 when the thermocouple is open (no connections). Default value is 0.

TEMPERATURE

(NC)

DIGITAL OUTPUT

(D[31:18])

+1600.00 0110 0100 0000 00

+1000.00 0011 1110 1000 00

+100.75 0000 0110 0100 11

+25.00 0000 0001 1001 00

0.00 0000 0000 0000 00

-0.25 1111 1111 1111 11

-1.00 1111 1111 1111 00

-250.00 1111 0000 0110 00

TEMPERATURE

(NC)

DIGITAL OUTPUT

(D[15:4])

+127.0000 0111 1111 0000

+100.5625 0110 0100 1001

+25.0000 0001 1001 0000

0.0000 0000 0000 0000

-0.0625 1111 1111 1111

-1.0000 1111 1111 0000

-20.0000 1110 1100 0000

-55.0000 1100 1001 0000

14-BIT THERMOCOUPLE

TEMPERATURE DATA RES FAULT

BIT

12-BIT INTERNAL TEMPERATURE

DATA RES SCV

BIT

SCG

BIT

BIT D31 D30 … D18 D17 D16 D15 D14 … D4 D3 D2 D1 D0

VALUE Sign MSB 210

(1024NC) …LSB 2-2

(0.25NC) Reserved 1 =

Fault Sign

MSB

(64NC)

…LSB 2-4

(0.0625NC) Reserved

1 =

Short

VCC

1 =

Short

GND

1 =

Open

Circuit

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

Applications Information

Noise Considerations

Because of the small signal levels involved, thermocou-

ple temperature measurement is susceptible to power-

supply coupled noise. The effects of power-supply noise

can be minimized by placing a 0.1FF ceramic bypass

capacitor close to the VCC pin of the device and to GND.

The input amplifier is a low-noise amplifier designed to

enable high-precision input sensing. Keep the thermo-

couple and connecting wires away from electrical noise

sources. It is strongly recommended to add a 10nF

ceramic surface-mount differential capacitor, placed

across the T+ and T- pins, in order to filter noise on the

thermocouple lines.

Thermal Considerations

Self-heating degrades the device’s temperature measure-

ment accuracy in some applications. The magnitude of the

temperature errors depends on the thermal conductivity

of the device package, the mounting technique, and the

effects of airflow. Use a large ground plane to improve the

device’s temperature measurement accuracy.

The thermocouple system’s accuracy can also be

improved by following these precautions:

• Usethelargestwirepossiblethatdoesnotshuntheat

away from the measurement area.

• If a 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 twisted

pair extension wire.

• Avoidsteeptemperaturegradients.

• Trytousethethermocouplewirewellwithinitstem-

perature rating.

• Usethepropersheathingmaterialinhostileenviron-

ments 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thermo-

couple resistance.

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

Ordering Information

Note: All devices are specified over the -40°C to +125°C operating temperature range.

+Denotes a lead(Pb)-free/RoHS-compliant package.

T = Tape and reel.

Package Information

For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or

“-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains

to the package regardless of RoHS status.

PART THERMOCOUPLE TYPE MEASURED TEMP RANGE PIN-PACKAGE

MAX31855KASA+ K -200NC to +1350NC8 SO

MAX31855KASA+T K -200NC to +1350NC8 SO

MAX31855JASA+ J -40NC to +750NC8 SO

MAX31855JASA+T J -40NC to +750NC8 SO

MAX31855NASA+ N -200NC to + 1300NC8 SO

MAX31855NASA+T N -200NC to + 1300NC8 SO

MAX31855SASA+ S +50NC to +1600NC8 SO

MAX31855SASA+T S +50NC to +1600NC8 SO

MAX31855TASA+ T -250NC to +400NC8 SO

MAX31855TASA+T T -250NC to +400NC8 SO

MAX31855EASA+ E -40NC to +900NC8 SO

MAX31855EASA+T E -40NC to +900NC8 SO

MAX31855RASA+ R -50NC to +1770NC8 SO

MAX31855RASA+T R -50NC to +1770NC8 SO

PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO.

8 SO S8+4 21-0041 90-0096

MAX31855

Maxim Integrated

Cold-Junction Compensated

Thermocouple-to-Digital Converter

Revision History

REVISION

NUMBER

REVISION

DATE DESCRIPTION PAGES

CHANGED

0 3/11 Initial release —

1 11/11 Corrected ESD protection value; added “S” and “R” type specifications 1, 2, 3, 8, 12

2 2/12

Corrected the thermocouple temperature conditions in the Thermal Characteristics

table and Table 1; added clarification to the Serial Interface section to help users

better understand how to communicate with the device; added a recommendation to

add a 10nF differential capacitor to the T+/T- pins in the Noise Considerations section

3, 8, 9, 11

MAX31855

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Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.

Maxim reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits) shown in the Electrical

Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.