2-3 wire RTD signal conditioner 0.1 degree accuracy

Hi Rajinder,

We have several TI Precision Designs that focus on RTD acquisition.  Please take a look at the following designs, they all focus on RTD sensor acquisition.  Because many of the errors are related to the full-scale signal, as you change the temperature ranges the expected errors will change as well.  Each of the designs include full error calculations that can be used to determine the expected error for modified temperature spans.

1.) TIPD120:  3-wire PT100 RTD Acquisition System Accurately Measures Temperature From -200°C - 850°C

-Feaures a digital SPI output with errors < 0.0125C over a -200C - 850C temperature span

2.) TIPD152:  0°C – 100°C, Hardware-Compensated Ratiometric 3-Wire PT100 RTD System Reference Design0°C – 100°C

-Features a digital SPI output with errors < 0.005C over a 0-100C temperature span

3.) TIPD161:  Analog Linearized 3-Wire PT100 RTD to 2-Wire 4-20mA Current Loop Transmitter Reference Design

-Features a 4-20mA output with hardware calibrated errors < 1C over a -200C-850C temperature span

4.) TIPD202:  Analog Linearized 3-Wire PT1000 RTD to 2-Wire 4-20mA Current Loop Transmitter Reference Design

-Features a 4-20mA output for PT1000 RTDs, hardware calibrated errors < 0.11C over a -50 - 250C temperature span

Hi Rajinder,

Follow the design guides in the document for both the schematic and PCB layout and you will achieve the same results.  Be careful to prevent PCB resistance from negatively affecting the RTD measurement by making proper Kelvin (4-wire) connections as described in the design guide and shown in the layout.