Hello
We are using the LM35DZ (TO-92 package) in one of our designs. Since this is through hole part, it is manually assembled on the PCB. We are seeing a high amount of failures after the parts are hand assembled.
3 out of 5 failed !!
To make sure that the parts are working fine before assembly, we had mounted them on a breadboard and tested its performance. It was working fine and reading about 270mV output. The Vcc is set to 12V and the output of the LM35 goes to a high impedance opamp. After the manual assembly, the output of the LM35 was seen at 6V irrespective of the temperature. We checked the assembly process and there is nothing out of the ordinary. We have used LM35 for over 10 years and never seen any failure.
We are attaching the image of the LM35 package for reference. These parts have been bought from Digikey and hence should be the original ones from TI.
We would like to know if these parts are the same which were sold 10 years ago. Any change in die or package or bond wiring between the old and new?
We note that the datasheet has been revised recently (2017) and wonder if any design changes could have made it less reliable while soldering.
Regards
Pappu
