LM35: LM35DT/NOPB Quality issue

Dear Michael - 

Thanks for the post. Please post their schematic and description of the problem here. 

I have send the information by email to you yesterday. 

Michael - 

To which email address did you send that to? I do not have anything in my inbox from you.

This forum is for solving these types of issues, inside this platform - as opposed to moving to email - please post the information here.

Can i attach the pdf file to here?STAGE 2.pdf

Michael - 

Yes, the PDF attachment came through - please also send a schematic. 

Also, just to set your expectation for next steps - if we cannot determine any issue with your hardware and we decide you need to return some parts for failure analysis - you will need to follow guidelines here to complete a return request submission form: 

https://www.ti.com/support-quality/additional-information/customer-returns.html 

the report have showed which line have fail. Please check it 

Sorry! Can i have feedback today?

Michael - 

The report is incomplete and really not useful for troubleshooting purposes without a schematic. Without knowing the input voltage and the way the devices are being connected and used, we won't be able to assist much further. Pictures or layout are generally helpful, too. 

Within the "report"  - the output voltages indicated are far outside the range of the device...4.3 / 10mV = 430C, to 4.9V / 10mV = 490C, both of which are impossible voltages with this part (indicates mishandling in general which may have shorted the devices and destroyed them or a mistake in measurement).  

Measuring the resistance between pins is really not helpful, I would suggest to not do that anymore - it is a wasted effort as it is meaningless to us. I would suggest to instead spend the time to provide a schematic and a detailed description of the testing measurements at temperatures. 

CAN you send us an official email? Our customer want to contact to yours.

Dear Michael - 

Here is the page for customer support:  https://ticsc.service-now.com/csm 

This is the feedback from our end user 

• I provided the schematic for the temp sensor.
• Disagree with the measurement mistake as we’ve found 12 pcs faulty parts
• Disagree with not helpful by measuring the resistance.
• Agree with the handling possibility.

 A03021 testi jig & sensor diagrams.pptx

Dear Michael - 

Thanks for more of the schematic. 

1. Understand they have parts which are not functioning correctly - we are in process of trying to determine possible reasons (via this post)

2. I am not sure why there is disagreement on the measurement of resistance. Simply put, the direct point here was that we don't specify any resistance between pins of the device, so it means little to us. We are interested here in the accurate voltage output of the device across the temperature range.

I would also ask to provide a complete schematic, at least as it related to the lines which are connected to the part and to the op amp, but cut off in the drawing supplied. From that drawing, I can see a 10M pull up to 3VDC, which most likely does not need to be there - it has no effect on the circuit. It would also be great to see input to ADC. 

Further, the low pass filter (4.7k and 0.1uF) is probably not needed either where it is, but it is hard to say without knowing if they have long leads and encountered some noise picked up by the wires going to the device. It is not clear yet the distance between the part and the op amp and then the op amp output to the ADC. This knowledge may be helpful if it could be shared. Even a representative schematic would be OK, if the actual parts left out of the drawing cannot be shared publicly. 

I just did a quick simulation of this and it also looks like they could drop the 30k to 18k and then enjoy full coverage to 150C without hitting the voltage rail too early, as the 30k looks to do. (with 10k and 18k for Ri and Rf, the range for 0C to 150C would then be 0V to 4.197V, versus with 10k and 30k, having only a range from about 1.1C to 125C before the output of the op amp hits 5V rail.)

The link I provided will allow you to submit devices for failure analysis, which we are glad to do, to reach an answer as soon as possible.

We have received the defect samples. Can we ship back to yours to evaluation? 

Michael - 

as stated at the start of this thread - for failure analysis - you will need to follow guidelines here to complete a return request submission form: 

https://www.ti.com/support-quality/additional-information/customer-returns.html  

So can you send us the address which we can send? We cannot find any information from the link which you give.