AM3352: 3.3V short circuit

Paul Richards

Part Number: AM3352

Hi,

We have a new design based on the AM3352 and TPS65217C PMIC.

Recently we've had several boards returned due to failure to power on. Subsequently we've identified a short on the 3.3V supply from LS2_OUT / VLDO4 in turn caused by AM3352 P6 (VDDSHV6) and P7 (VDDSHV1) being shorted to ground. All boards were initially functional but failed months later during operation.

We understand that VDDSHV6 and VDDSHV1 are rated to 100 mA and 50 mA respectively, however we have been unable to identify the source of any over current draw.

Does the fact that the same two balls (P6 and P7) are shorted, while other balls for the same rails (including adjacent balls P5 and P8) are not, help narrow down the possible I/O that may be the cause of the problem?

Thanks in advance,

Paul

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Please check that you do not have any external voltage applied to AM335x I/O pins while the device is unpowered. AM335x I/O pins are not fail-safe, see parameter "Steady state max voltage at all IO pins" in section 5.1 of the AM335x Datasheet Rev. J. Also check Note 8 below the table.

0 Paul Richards over 8 years ago in reply to Biser Gatchev-XID

Prodigy 205 points

Thanks Biser, we'll review our non fail-safe I/O, particularly at startup / shutdown for anything out of spec.

0 Paul Richards over 8 years ago in reply to Paul Richards

Prodigy 205 points

Hi Biser,

Thanks - we've identified some possible candidates and have no further specific questions at this time so I'll close this ticket.

Paul

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AM3352: 3.3V short circuit