Single Chip 2-Wire Loop Powered, 4 to 20mA Current Loop RTD Temperature Transmitter Reference Design
This product has been released to the market and is available for purchase. For some products, newer alternatives may be available.

Description & Features

Technical documentation

Support & Training

Order Now

See the Important Notice and Disclaimer covering reference designs and other TI resources.

Key Document


In general, for portable 2-wire 4 to 20mA current loop applications, the system power consumption needs to be considered carefully. The conventional approach of using a high bridge excitation voltage and an operational amplifier to achieve a full-scale ADC input voltage increases chip count and overall power consumption. An additional external voltage regulator is also needed to excite the bridge sensor and supply the microcontroller from the same voltage source. Since the goal for this reference design is to maintain low power consumption and low cost solution. This solution utilizes the integrated ADC and operational amplifiers (OAs) of a microcontroller. In order to cut down the cost, the ADC/DAC use the main supply voltage as its reference voltage instead of including an external reference or selecting a more expensive ADC/DAC that features an internal reference. Leveraging the integrated peripherals of MCU enables low component count and low cost. This reference design is based on a mixed signal microcontroller, specifically an MSP430F2274.

  • Analog functionality fully integrated into microcontroller
  • Sensor input compatible with 2-wire PT100 RTD probe only
  • Temperature range for RTD -200°C to +850°C
  • Input power supply range: 10V to 33V DC
  • 4 to 20mA current loop output signal
  • Maximum measured error: better than ±2.5ºC
  • Implements ratiometric measurement
  • Design to meet IEC 61000-4 requirement
  • Operating temperature range -40°C to +85°C

See the Important Notice and Disclaimer covering reference designs and other TI resources.


Schematic/Block Diagram

Quickly understand overall system functionality.

Download Schematic

Design Guide

Get results faster with test and simulation data that's been verified.

Download Design Guide

TI Devices (2)

Order samples, get tools and find more information on the TI products in this reference design.

Part Number Name Product Family Sample & Buy Design Kits & Evaluation Modules
MSP430F2274  16 MHz MCU with 32KB Flash, 1KB SRAM, 10-bit ADC, 2 OpAmp, I2C/SPI/UART  Microcontrollers (MCUs)  Sample & Buy View Design Kits & Evaluation Modules
TPS7A16  100-mA, 60-V, ultra-low-IQ, low-dropout (LDO) voltage regulator with power good and enable  Power management  Sample & Buy View Design Kits & Evaluation Modules

CAD/CAE symbols

Part # Package | Pins CAD File (.bxl) STEP Model (.stp)
MSP430F2274 Download -
Download Download
Download -
TPS7A16 Download Download
Download Download

Texas Instruments and Accelerated Designs, Inc. have collaborated together to provide TI customers with schematic symbols and PCB layout footprints for TI products.

Step 1: Download and install the free download.

Step 2: Download the Symbol and Footprint from the CAD.bxl file table.

Technical documentation

See the Important Notice and Disclaimer covering reference designs and other TI resources.

User guide (1)
Title Type Size (KB) Date
PDF 10401 30 Jan 2015
Design files (5)
Title Type Size (KB) Date
ZIP 1222 30 Jan 2015
PDF 161 30 Jan 2015
ZIP 301 30 Jan 2015
PDF 43 30 Jan 2015
PDF 653 30 Jan 2015
Related Tools & Software

Reference Designs (5)

Support & training

TI E2E™ forums with technical support from TI engineers

Search our extensive online knowledge base where millions of technical questions and answers are available 24/7.

Search answers from TI experts

Content is provided 'AS IS' by the respective TI and Community contributors and does not constitute TI specifications.
See terms of use.

If you have questions about quality, packaging, or ordering TI products visit our Support page.

Technical articles