Datasheet LTC2986, LTC2986-1 (Analog Devices)

LTC2986/LTC2986-1 Multi-Sensor High Accuracy Digital Temperature Measurement System with EEPROM
FEATURES DESCRIPTION
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 0.1°C accuracy and 0.001°C resolution. The LTC2986 can Configuration Data 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
APPLICATIONS
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 APPLICATION Thermocouple Measurement with Automatic Cold Junction Compensation Typical Temperature Error Contribution
2.85V TO 5.25V 0.5 1k LTC2986-1 0.4 0.1µF 0.3 24-BIT THERMISTOR 1k ∆∑ ADC 0.2 THERMOCOUPLE 0.1 0 LINEARIZATION/ SPI ERROR (°C) –0.1 INTERFACE R FAULT DETECTION SENSE –0.2 3904 DIODE 24-BIT 2k °C/°F ∆∑ ADC RTD –0.3 –0.4 4 3 –0.5–200 0 200 400 600 800 1000 1200 1400 PT-100 RTD 24-BIT TEMPERATURE (°C) ∆∑ ADC 2 29861 TA01b 1 VREF (15ppm/°C) EEPROM COM 29861 TA01a 29861fa For more information www.linear.com/LTC2986 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Pin Configuration Complete System Electrical Characteristics ADC Electrical Characteristics Reference Electrical Characteristics Digital Inputs and Digital Outputs LTC2986-1 EEPROM Characteristics Typical Performance Characteristics Pin Functions Block Diagram Test Circuits Timing Diagram Overview Applications Information EEPROM Overview (LTC2986-1) EEPROM Read/Write Validation EEPROM Write Operation EEPROM Read Operation (LTC2986-1) Thermocouple Measurements Diode Measurements RTD Measurements Thermistor Measurements Global Configuration Register Input Overvoltage Protection – Overview Active Analog Temperature Sensors Direct ADC Measurements 2- and 3-Cycle Conversion Modes Running Conversions Consecutively on Multiple Channels Entering/Exiting Sleep Mode MUX Configuration Delay Reference Considerations Custom Thermocouples Custom RTDs Custom Thermistors Package Description Revision History Typical Application Related Parts