View the Important Notice for TI Designs covering authorized use, intellectual property matters and disclaimers.
- 2-Wire Isolated Temperature Sensor Design Guide (Rev. B)
(PDF 1998 KB)
20 Jun 2016 72 views
In order to provide system designers a new cost-effective and easy alternative to assured precision temperature measurement, this reference design discusses the new tiny 2-pin digital output IC temperature sensor with single wire pulse count interface that enhances reliability and greatly simplifies the design of galvanic isolation architecture for sending both power and unidirectional data through same low profile transformer and remote operation. In addition, with fewer error sources, computation of error budget is easier. Cost budgets, accuracy, size and simplicity of interfacing with other circuit elements are main factors in selecting a sensor to do a job and this reference design system tremendously helps in meeting all these requirements. With less-than 0.25°C maximum measured error over temperature range -50°C to 150°C, functional isolation of 400VRMS and IEC61000-4-4 pre-compliance testing, this design significantly reduces the design time for development of high-accuracy temperature measurement systems.
- Allows Single Low-Profile Transformer for Power and Data Isolation While Eliminating the Need for Optocoupler or Digital Isolator on Data Line
- Power and Data Coexist on 2–Wire Interface for Remote Temperature Sensing Across Isolation
- No Need of System Level Calibration Unlike Thermistors
- Replacement for RTDs and NTC or PTC Thermistors
- Eliminates High-Precision Active or Passive Components
- Functional Isolation of 400 VRMS and Dielectric up to 2500-V AC for 60 seconds
- Pre-Compliance Testing: Meets IEC61000-4-4 EFT (Level 4): ±2 kV – Class-A
- Accuracy Over Temperature:
- Measured Error Using LUT: < 0.25ºC (-35ºC to 150ºC)
- Measured Error Using 1st Order Transfer Function: < 0.25ºC (15ºC to 100ºC)
- Guaranteed Limits from LMT01 Datasheet Using LUT: < 0.5 max. (-20ºC to 90ºC), 0.62 max. (90ºC to 150ºC), < 0.7 max. (-50ºC to -20ºC)