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MSP430G2432: RESET pin drop issue on MSP430G2432

Part Number: MSP430G2432

Dear Experts

My customer followed our EVM for the DVCC and RESET circuit design as follows:

They found RESET drop to below 2V which makes MSP430 hangs up when battery drop to 9V but DVCC still keep 3.3V.

5 pcs shows this situation over totally 2000pcs products.

And this issue happens sometimes (not always) in those 5pcs failed products.

Do  you have any comment about this issue?

Should I do any further test or just send those failed for FA analysis?

Thanks for your comment.

  • Hello Jefferey,

    What EVM did the customer follow? The pullup resistance is quite strong as 47 kOhm is typically recommended and this could be causing issues with the 5 failing devices. Would it be possible to compare the current draw from the LDO of a failing vs passing unit? Does the issue follow the MSP430 or LDO?

    Regards,
    Ryan
  • Dear Ryan

    Sorry for my typo.

    Customer originally uses 47KOhm but the voltage of RESET pin drop to 2.0V which makes MSP430 hangs up.

    So they try 2.2KOhm which makes the RESET back to 2.8V.

    This method works but customer still wonder why it happens.

    Could you share the internal circuit of MSP430 DVCC and RESET or other information to help us?  

    Thanks.

  • Jefferey,

    What is the output current allowance of the LDO, and are any other devices connected to the LDO output? Are the proper Vcc decoupling capacitors being used? The reset schematic/block diagram is provided by Figure 2-1/2-4 in the User's Guide but the issue most likely has to deal with the custom PCB design, can the customer share schematics and layout images?

    Edit: This issue was further handled offline.

    Regards,
    Ryan