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TPS782: tps78223ddct quiescent current issue in case of very low current

MichRFT
Expert 2110 points
Part Number: TPS782
Other Parts Discussed in Thread: MSP430FR5969

Hello,

We are testing PCBA with a MSP430FR5969 and a tps78223ddct. The input and output capacitor of the tps78223 are 1uF. The input voltage is 3V, regulated voltage 2.3V.

During LPM3 mode of the microcontroller the whole pcba current consumption should be around 7uA.

ON the first 30 PCBA, around 5 PCBA current consumption is more than 30uA. If we change the tsp78223, the current consumption can change to the expected 7uA. If we change the ouput 1uF ceramic capacitor to a higher value without changing the tps78223, the current consumption is measured at 7uA for some PCBA. For other PCBA, the capacitor change to higher value increases the quiescent current consumption.

Do you have any advice for very low current?

Best regards

Mich

  • 0
    TI__Guru 50060 points
    HI Mich,

    Leakage can come from a number of causes. Different dielectrics of capacitors have different leakages. Additionally PCB contamination can contribute to unexpected leakage paths. This is more common with very small components where the physical distance between terminals minimal.

    If you put the TPS78223 that was measuring as having a higher than expected leakage back on the PCB, do you get the same measurement?

    I am curious to hear what might be causing this.
  • 0 in reply to JCHK
    Expert 2110 points
    Hi JCHK,
    You are right, I switched 2 tps78223 between 2 PCBA and the issue stays on the same PCBA. So the issue is the PCBA.
  • 0 in reply to MichRFT
    TI__Guru 50060 points
    Glad to hear you found the root cause!

    Thank you for using TI in your designs!

    Regards,