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TPS76801-EP: TPS76801 Quiescent current issue.

Stanley Alfred
Prodigy 50 points
Part Number: TPS76801-EP

Tool/software:

Hi Guys,


We are  designing a battery powered system. when we run the ultra low power mode, the TPS76801QDR (Adjustable version) part consumes 380uA.  As per the datasheet, quiescent current for TPS76801QDR would be 85uA.


To confirm this issue, we have tested the quiescent current on Fixed version from same family.  Fixed version part number is TPS76833QDR.  We have tested this part on General Purpose Board. Here we didn't connect any load. (By the way we are ensure there is no leakage on output pin).  Even on open circuit, the TPS76833QDR also consumes 380uA.

Iin = Iq + Iload.

Here,

Iload = 0A.  Since it is an open circuit.

Therefore,

Iin = Iq.  


We have added the block diagram of the test setup below. Please address me, if anybody facing the same issue.

We measured the current by connecting ammeter in series at Positive terminal.
  

Also, We measured the current by connecting ammeter in series at ground terminal.

  • 0
    TI__Mastermind 37075 points

    Hi Stanley,

    There are other aspects to the design which may cause additional current leakage.  The capacitors and resistor divider on the device will increase the leakage current.  If the capacitors have had hand soldering or rework, they may very well have increased in current leakage and should be (gently) replaced with a fresh capacitor.  Please make sure the PCB is thoroughly cleaned and free of flux residue from the assembly process.  Using isopropyl alcohol to wash the PCB followed immediately by cleaning with distilled water and finally a distilled water bath will usually eliminate most, if not all, contaminates.  Please also review this app note for test setup concerns:

    https://www.ti.com/lit/an/slyt558/slyt558.pdf

    Thanks,

    Stephen