ULN2003A: ULN2003ADR Failure issue

Hi Muhammed,

I have a few questions about your issue:

1. +12V and VCC_12V are the same 12V rail, correct?

2. How much current flows through each channel of the device?

3. Is it known when the "event" occurs? Is it during DC on or is it during switching?

4. Do you have any scopeshots that describe the event?

1 . Both are same 12V

2 . Maximum 30 mA

3. ya . It happen when during switching

4. Actually these relays are fan controlling relays, Combination of these relay adjusted the speed of fan(230AC) by adding capacitor

Hi Muhammed,

When you say "failed" what exactly is the failure mode. Does the board not work any more? Is there damage to the device? Does it recover when the system is reset?

Since only a few boards have failed I think the best way to move forward with this support is with scopshots.

If possible one from a board that works and one from a board that fails so that we can compare what exactly is going on.

Failure mode means that, Here relay ground control is set by ULN driver, But without input selection: ULN driver connect the ground to relay( ON full time),  It means that relay activated by full time without any input applied to the ULN IC.