LM74500-Q1: Test condition for electrical characteristics

Hi Sherry,

LM74500-Q1 has been designed majorly fo automotive applications where the temperature requirements aren't as high as 150C. Also, operating at temperatures higher than 125C leads to decreased operating lifetime. 

Is there any specific parameter in which the customer is interested whose variation in temperature they are concerned about? I can then check with our design to see if the expected variation in that parameter with temperature.

Regards

Divyanshu

Hi Divyanshu,

Thanks for your reply!

Yes, my customer's application is automotive TCU which has a higher temperature, our device will always work under Tj=135C, so my customer wants to know whether we can promise the accuracy of electrical characteristics listed in the datasheet. In my understanding, the electrical characteristics may be different with the value listed in the datasheet when Tj>125C, right?

Thanks & Best regards,

Sherry

Hi Sherry,

As per my understanding the electrical parameters should not change much when temp is changed from 125 to 135C. Let me check once with my team internally and get back to you.

Best regards

Divyanshu

Hi Sherry,

Can you confirm if 135C is Tj or the ambient temperature of the system?

Regards

Divyanshu

Hi Divyanshu,

The ambient temp for TCU is 105C. Out device is inside the TCU box. And the ambient temp inside the TCU box is around 125C, so our device's junction temp is around 135C. Please help evaluate how our electrical parameters change during 125C-150C junction temp?

Thanks & Best Regards,

Sherry

Hi Sherry,

Let me check and get back to you.

Best regards

Divyanshu

Hi Divyanshu,

1. I still want to know whether we can guarantee our electrical characteristics when Tj>125C? If not, how they change? My customer needs to evaluate the impact to the project.

2. Our device' max Tj is 150C. Why the test condition is -40 to 125C instead of -40C to 150C? My customer wants to know whether our test condition( -40 to 125C) meet AECQ100 Grade 1 requirement?

Thanks & Best Regards,

Sherry

Hi Divyanshu,

Thanks for your reply!

My customer will ask why we list -40-125C test condition in the datasheet instead of -40-150C. Will we change the test condition to -40C to 150C in the future? If not, they will ask me to provide evidence how we can guarantee our specs when Tj>125......

Thanks & Brest Regards,

Sherry

Hi Sherry,

Since we are taking this up over e-mail, please close the thread here.

Best regards

Divyanshu