LM7310: Leakage at IN side when reverse blocking

Hi Hardy,

Thanks for reaching out to us. Most of the folks are on leave now due to year end. We will get back to you on 03 Jan 22. Sorry for the delay. 

Hi Hardy,

1. There is no supply at VIN?

2. When 12V at out goes away then 0.77V goes to zero?

Regards

Kunal Goel

Hi Kunal,

1. Yes, I only add 12V at OUT.

2. Yes

Best regards,

Hardy

Hi Hardy,

1. You see this on both channels of EVM?

2.  Can you try removing device and repeat test, just to be sure that the leakage is through device or some other path?

3. What does this cross mean on VIN line, have you cut trace?

Regards

Kunal Goel

Hi Kunal,

1. I only use U1 path.

2. Could you please help to check it on EVM? Due to personal health issue, I will not enter office recently.

3. Yes, I cut the trace to make sure there is no other path enter IN pin.

Best regards,

Hardy

Hi Hardy,

Let me check EVM stock, otherwise I will order one and test.

Regards

Kunal Goel

Hi Kunal,

Thanks for your help. If you have any update, please let me know.

By the way, could you please provide the EVM board file to me also?

Best regards,

Hardy

Hi Hardy,

PFA board files.

Regards

Kunal GoelLM73100EVM_external_share.zip

Hi Hardy,

If the input is left floating completely, there could be a small voltage build up due to leakage current. The leakage current should be very small in uA range and a slight amount of loading should discharge the input completely. In real application there may be some loading at VIN which will discharge VIN. 

Let me know if this answers your concern?

Regards

Kunal Goel

Hi Kunal,

Thanks for your reply.

I sent the E-mail to you for related data. Customer modified the EVM to their schematic. They found the leakage voltage is about 1.48V.

1. Look like this phenomenon is same with our test. Correct?

2. Do we suggest customer to add dummy load on Vin pin?

3. If Q2 yes, how to to calculate this resistor value or what value are you recommendation?

Best regards,

Hardy