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ULN2003A: ULN2003ADR Failure issue

Muhammed Safvan
Prodigy 190 points
Part Number: ULN2003A

Here

Vin = 4v

COM = 12 v (20ma)

ULN2003ADR IC of some boards are failed, There is no idea How to failed it,,, Can you give the possible response?

  • 0
    TI__Mastermind 32650 points

    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?

  • 0 in reply to Shreyas Dmello
    Prodigy 190 points

    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

  • 0 in reply to Muhammed Safvan
    TI__Mastermind 32650 points

    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.

  • 0 in reply to Shreyas Dmello
    Prodigy 190 points

    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.

  • 0 in reply to Muhammed Safvan
    TI__Mastermind 32650 points

    Hi Muhammaed,

    Let me confirm the failure mode: when no input is sent to the ULN device, the channel still connects to GND and turns on the load.

    When does this event occur? During switching of other loads or in DC conditions?

    Is this event consistent over multiple devices?

    Does this occur over all channels or is only one channel susceptible to this event?

    Please share a scopeshot of this event so that we can further narrow down the issue