Measurement System. LTC2986 Datasheet

LTC2986 System. Datasheet pdf. Equivalent

LTC2986 Datasheet
Recommendation LTC2986 Datasheet
Part LTC2986
Description Multi-Sensor High Accuracy Digital Temperature Measurement System
Feature LTC2986; LTC2986/LTC2986-1 FEATURES Multi-Sensor High Accuracy Digital Temperature Measurement System with .
Manufacture Linear Technology
Datasheet
Download LTC2986 Datasheet




Linear Technology LTC2986
LTC2986/LTC2986-1
FEATURES
Multi-Sensor High
Accuracy Digital Temperature
Measurement System with EEPROM
DESCRIPTION
nn Directly Digitizes 2-, 3- or 4-Wire RTDs,
Thermocouples, Thermistors, and Diodes
nn On-Chip EEPROM (LTC2986-1) Stores Channel
Configuration Data and Custom Coefficients
nn Single 2.85V to 5.25V Supply
nn 10 Flexible Inputs Allow Interchanging Sensors
nn Automatic Thermocouple Cold Junction Compensation
nn Built-In Standard and User-Programmable Coefficients
for Thermocouples, RTDs and Thermistors
nn Measures Negative Thermocouple Voltages
nn Automatic Burn Out, Short-Circuit and Fault Detection
nn Buffered Inputs Allow External Protection
nn Simultaneous 50Hz/60Hz Rejection
nn Includes 15ppm/°C (Max) Reference
nn Includes Special Protection Modes
APPLICATIONS
nn Direct Thermocouple Measurements
nn Direct RTD Measurements
nn Direct Thermistor Measurements
nn Custom Sensor Applications
The LTC®2986 measures a wide variety of temperature
sensors and digitally outputs the result, in °C or °F, with
0.1°C accuracy and 0.001°C resolution. The LTC2986 can
measure the temperature of virtually all standard (Type B,
E, J, K, N, S, R, T) or custom thermocouples, automatically
compensate for cold junction temperatures and linearize
the results. The device can also measure temperature
with standard 2-, 3- or 4-wire RTDs, thermistors, and
diodes. The LTC2986 includes excitation current sources
and fault detection circuitry appropriate for each type of
temperature sensor.
The LTC2986/LTC2986-1 are 10-channel software and pin-
compatible versions of the 20-channel LTC2983/LTC2984.
Additional features include special modes that enable easy
protection in universal multi-sensor applications, custom
tables for generic ADC readings, and direct temperature
readout from active analog temperature sensors. The
LTC2986-1 is the EEPROM version of the LTC2986.
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
Patents Pending
TYPICAL APPLICATION
Thermocouple Measurement with Automatic Cold Junction Compensation
2.85V TO 5.25V
1k
0.1µF
1k
24-BIT
∆∑ ADC
LTC2986-1
RSENSE
2k
43
PT-100
RTD
2
1
COM
24-BIT
∆∑ ADC
LINEARIZATION/
FAULT DETECTION
SPI
INTERFACE
°C/°F
24-BIT
∆∑ ADC
VREF (15ppm/°C)
EEPROM
29861 TA01a
For more information www.linear.com/LTC2986
Typical Temperature Error
Contribution
0.5
0.4
0.3 THERMISTOR
0.2 THERMOCOUPLE
0.1
0
–0.1
–0.2 3904 DIODE
–0.3 RTD
–0.4
–0.5
–200 0
200 400 600 800 1000 1200 1400
TEMPERATURE (°C)
29861 TA01b
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Linear Technology LTC2986
LTC2986/LTC2986-1
TABLE OF CONTENTS
Features............................................................................................................................. 1
Applications........................................................................................................................ 1
Typical Application ................................................................................................................ 1
Description......................................................................................................................... 1
Absolute Maximum Ratings...................................................................................................... 3
Order Information.................................................................................................................. 3
Pin Configuration.................................................................................................................. 3
Complete System Electrical Characteristics................................................................................... 4
ADC Electrical Characteristics................................................................................................... 4
Reference Electrical Characteristics............................................................................................ 5
Digital Inputs and Digital Outputs............................................................................................... 5
LTC2986-1 EEPROM Characteristics............................................................................................ 6
Typical Performance Characteristics........................................................................................... 7
Pin Functions......................................................................................................................10
Block Diagram.....................................................................................................................11
Test Circuits.......................................................................................................................12
Timing Diagram...................................................................................................................12
Overview........................................................................................................................... 13
Applications Information........................................................................................................17
EEPROM Overview (LTC2986-1)........................................................................................................................... 23
EEPROM Read/Write Validation............................................................................................................................. 23
EEPROM Write Operation...................................................................................................................................... 23
EEPROM Read Operation (LTC2986-1).................................................................................................................. 24
Thermocouple Measurements............................................................................................................................... 25
Diode Measurements............................................................................................................................................. 28
RTD Measurements............................................................................................................................................... 32
Thermistor Measurements..................................................................................................................................... 51
Global Configuration Register................................................................................................................................ 60
Input Overvoltage Protection – Overview.............................................................................................................. 60
Active Analog Temperature Sensors...................................................................................................................... 66
Direct ADC Measurements..................................................................................................................................... 70
2- and 3-Cycle Conversion Modes......................................................................................................................... 75
Running Conversions Consecutively on Multiple Channels.................................................................................... 75
Entering/Exiting Sleep Mode.................................................................................................................................. 76
MUX Configuration Delay....................................................................................................................................... 76
Reference Considerations...................................................................................................................................... 76
Custom Thermocouples..........................................................................................................77
Custom RTDs......................................................................................................................80
Custom Thermistors..............................................................................................................83
Package Description.............................................................................................................88
Revision History..................................................................................................................89
Typical Application...............................................................................................................90
Related Parts......................................................................................................................90
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Linear Technology LTC2986
LTC2986/LTC2986-1
ABSOLUTE MAXIMUM RATINGS
(Notes 1, 2)
Supply Voltage (VDD).................................... –0.3V to 6V
Analog Input Pins (CH1 to
CH10, COM).................................. –0.3V to (VDD + 0.3V)
Input Current (CH1 to CH10, COM)....................... ±15mA
Digital Inputs (CS, SDI,
SCK, RESET)................................. –0.3V to (VDD + 0.3V)
Digital Outputs (SDO, INTERRUPT). –0.3V to (VDD + 0.3V)
VREFP......................................................... –0.3V to 2.8V
Q1, Q2, Q3, LDO, VREFOUT, VREF_BYP (Note 18)
Reference Short-Circuit Duration...................... Indefinite
Operating Temperature Range
LTC2986C................................................. 0°C to 70°C
LTC2986I..............................................–40°C to 85°C
LTC2986H........................................... –40°C to 125°C
PIN CONFIGURATION
TOP VIEW
VREFOUT 13
VREFP 14
GND 15
CH1 16
CH2 17
CH3 18
CH4 19
CH5 20
CH6 21
CH7 22
CH8 23
CH9 24
48 Q1
47 Q2
46 Q3
45 VDD
44 GND
43 LDO
42 RESET
41 CS
40 SDI
39 SDO
38 SCK
37 INTERRUPT
LX PACKAGE
48-LEAD (7mm × 7mm) PLASTIC LQFP
TJMAX = 150°C, θJA = 57°C/W
ORDER INFORMATION http://www.linear.com/product/LTC2986#orderinfo
LEAD FREE FINISH
TRAY
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC2986CLX#PBF
LTC2986CLX#PBF
LTC2986LX
48-Lead (7mm × 7mm) LQFP
0°C to 70°C
LTC2986ILX#PBF
LTC2986ILX#PBF
LTC2986LX
48-Lead (7mm × 7mm) LQFP
–40°C to 85°C
LTC2986HLX#PBF
LTC2986HLX#PBF
LTC2986LX
48-Lead (7mm × 7mm) LQFP
–40°C to 125°C
LTC2986CLX-1#PBF
LTC2986CLX-1#PBF
LTC2986LX-1
48-Lead (7mm × 7mm) LQFP
0°C to 70°C
LTC2986ILX-1#PBF
LTC2986ILX-1#PBF
LTC2986LX-1
48-Lead (7mm × 7mm) LQFP
–40°C to 85°C
LTC2986HLX-1#PBF
LTC2986HLX-1#PBF
LTC2986LX-1
48-Lead (7mm × 7mm) LQFP
–40°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information www.linear.com/LTC2986
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