Datasheet LTC2983 (Analog Devices)

LTC2983 Multi-Sensor High Accuracy Digital Temperature Measurement System
FEATURES DESCRIPTION
n Directly Digitize RTDs, Thermocouples, Thermistors The LTC®2983 measures a wide variety of temperature and Diodes sensors and digitally outputs the result, in °C or °F, with n Single 2.85V to 5.25V Supply 0.1°C accuracy and 0.001°C resolution. The LTC2983 can n Results Reported in °C or °F measure the temperature of virtually all standard (type B, n 20 Flexible Inputs Allow Interchanging Sensors E, J, K, N, S, R, T) or custom thermocouples, automatically n Automatic Thermocouple Cold Junction Compensation compensate for cold junction temperatures and linearize n Built-In Standard and User-Programmable Coefficients the results. The device can also measure temperature with for Thermocouples, RTDs and Thermistors standard 2-, 3- or 4-wire RTDs, thermistors and diodes. It n Configurable 2-, 3- or 4-Wire RTD Configurations has 20 reconfigurable analog inputs enabling many sen- n Measures Negative Thermocouple Voltages sor connections and configuration options. The LTC2983 n Automatic Burn Out, Short-Circuit and Fault Detection includes excitation current sources and fault detection n Buffered Inputs Allow External Protection circuitry appropriate for each type of temperature sensor. n Simultaneous 50Hz/60Hz Rejection The LTC2983 allows direct interfacing to ground referenced n Includes 15ppm/°C (Max) Reference (I-Grade) sensors without the need for level shifters, negative supply
APPLICATIONS
voltages, or external amplifiers. All signals are buffered and n simultaneously digitized with three high accuracy, 24-bit ∆∑ Direct Thermocouple Measurements n ADCs, driven by an internal 15ppm/°C (maximum) reference. Direct RTD Measurements n L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Direct Thermistor Measurements Technology Corporation. All other trademarks are the property of their respective owners. n Custom Sensor Applications Patents Pending
TYPICAL APPLICATION Thermocouple Measurement with Automatic Cold Junction Compensation Typical Temperature Error Contribution
2.85V TO 5.25V 1k 0.5 LTC2983 0.4 0.1µF 24-BIT 0.3 THERMISTOR 1k ∆∑ ADC 0.2 THERMOCOUPLE 0.1 0 ERROR (°C) –0.1 LINEARIZATION/ SPI FAULT DETECTION INTERFACE –0.2 3904 DIODE RSENSE RTD 24-BIT 2k °C/°F –0.3 ∆∑ ADC –0.4 –0.5–200 0 200 400 600 800 1000 1200 1400 4 3 TEMPERATURE (°C) PT-100 2983 TA01b RTD 24-BIT ∆∑ ADC 2 1 VREF (10ppm/°C) 2983 TA01a 2983fc For more information www.linear.com/LTC2983 1 Document Outline Features Applications Typical Application Description Absolute Maximum Ratings Order Information Complete System Electrical Characteristics Pin Configuration ADC Electrical Characteristics Reference Electrical Characteristics Digital Inputs and Digital Outputs Typical Performance Characteristics Pin Functions Block Diagram Test Circuits Timing Diagram Overview Applications Information Thermocouple Measurements Diode Measurements RTD Measurements Thermistor Measurements Direct ADC Measurements Supplemental Information Fault Protection and Anti-Aliasing 2- and 3-Cycle Conversion Modes Running Conversions Consecutively on Multiple Channels MUX Configuration Delay Global Configuration Register Custom Thermocouples Custom RTDs Custom Thermistors Package Description Revision History Typical Application Related Parts