LTC2986/LTC2986-1 Multi-Sensor High Accuracy Digital Temperature Measurement System with EEPROM Fea T Descrip T n Directly Digitizes 2-, 3-, or 4-Wire RTDs, The LTC 2986 measures a wide variety of temperature Thermocouples, Thermistors, and Diodes sensors and digitally outputs the result, in C or F, with n On-Chip EEPROM (LTC2986-1) Stores Channel 0.1C accuracy and 0.001C resolution. The LTC2986 can ConfigurationData and Custom Coefficients measure the temperature of virtually all standard (Type B, n Single 2.85V to 5.25V Supply E, J, K, N, S, R, T) or custom thermocouples, automatically n 10 Flexible Inputs Allow Interchanging Sensors compensate for cold junction temperatures and linearize n Automatic Thermocouple Cold Junction Compensation the results. The device can also measure temperature n Built-In Standard and User-Programmable Coefficients with standard 2-, 3-, or 4-wire RTDs, thermistors, and for Thermocouples, RTDs and Thermistors diodes. The LTC2986 includes excitation current sources n Measures Negative Thermocouple Voltages and fault detection circuitry appropriate for each type of n Automatic Burn Out, Short-Circuit and Fault Detection temperature sensor. n Buffered Inputs Allow External Protection The LTC2986/LTC2986-1 are 10-channel software and pin- n Simultaneous 50Hz/60Hz Rejection compatible versions of the 20-channel LTC2983/LTC2984. n Includes 15ppm/C (Max) Reference Additional features include special modes that enable easy n Includes Special Protection Modes protection in universal multi-sensor applications, custom tables for generic ADC readings, and direct temperature a T readout from active analog temperature sensors. The n Direct Thermocouple Measurements LTC2986-1 is the EEPROM version of the LTC2986. n Direct RTD Measurements L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear n Direct Thermistor Measurements Technology Corporation. All other trademarks are the property of their respective owners. Patents Pending n Custom Sensor Applications Typical a T Thermocouple Measurement with Automatic Cold Junction Compensation Typical Temperature Error Contribution 2.85V TO 5.25V 0.5 1k LTC2986-1 0.4 0.1F 0.3 THERMISTOR 24-BIT 1k ADC 0.2 THERMOCOUPLE 0.1 0 SPI 0.1 LINEARIZATION/ INTERFACE FAULT DETECTION R SENSE 0.2 3904 DIODE 24-BIT 2k C/F RTD ADC 0.3 0.4 4 3 0.5 200 0 200 400 600 800 1000 1200 1400 PT-100 TEMPERATURE (C) 24-BIT RTD ADC 2 29861 TA01b 1 V (15ppm/C) EEPROM REF COM 29861 TA01a 29861f 1 For more information www.linear.com/LTC2986 ERROR (C) ion pplica ions pplica ion uresLTC2986/LTC2986-1 Table o F c T Ts 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 .................................................................................................................................... 50 Global Configuration Register ............................................................................................................................... 59 Input Overvoltage Protection Overview.............................................................................................................. 59 Active Analog Temperature Sensors ..................................................................................................................... 65 Direct ADC Measurements .................................................................................................................................... 69 2- and 3-Cycle Conversion Modes ........................................................................................................................ 74 Running Conversions Consecutively on Multiple Channels ................................................................................... 74 Entering/Exiting Sleep Mode ................................................................................................................................. 75 MUX Configuration Delay ...................................................................................................................................... 75 Reference Considerations ..................................................................................................................................... 75 Custom Thermocouples .........................................................................................................76 Custom RTDs .....................................................................................................................79 Custom Thermistors .............................................................................................................82 Package Description ............................................................................................................87 Typical Application ..............................................................................................................88 Related Parts .....................................................................................................................88 29861f 2 For more information www.linear.com/LTC2986 en on