LM358: LM358

Hi Amruta,

I wouldn't do that. The LM358 is a low cost OPAmp. I would use a precision OPAmp for that, or a XTR. Or even a precise ADC could be used.

A PT100 sensor shows a resistance change of about 0.39R per °C. A measuring current of 1mA gives a voltage change of 390µV per °C. The LM358 has an input offset voltage of up to 9mV. This means a measuring error of up to +/-23°C. Even if you callibrate the offset voltage you will suffer from offset voltage drift of eventually more than 20µV/°C. So, when the ambient temperature changes by 20°C the temperature measurement can show an error of more than +/-1°C. Additionally the longterm drift can be an issue which isn't specified for the LM358 at all.

No, I wouldn't use the LM358 for a PT100 application. But why not using a XTR? You can easily convert the output current into a voltage by the help of a burden resistor.

Kai

Hi,
Thank you for quick reply. LM 358 is a low cost and i want low cost effective solution. Xtr is a little costly and it not fit in cost . Which is other cost effective solution for this project.

Amruta,

Try TLV333, it has 15uV input offset error.