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TPS61161 FB pin fixed at 600mV cannot be changed.

Dale Wlasitz
Intellectual 1080 points
Other Parts Discussed in Thread: TPS61161

Customer has used the TPS61161 with good success on the early samples they received.  Their easy scale programming has not changed.  The only change has been new silicon and they are claiming the FB pin ramps to and remains fixed at 600mV from power on.

The application is relatively straight forward, the input voltage is 5.1Volts.  They are driving 6 series LED's at 20mA and are using a 10 ohm sense resistor.

When they used the sample silicon they were able to use Easy Scale as expected, the top side markings of the sample silicon used is:

XBZR

77K

D6HL

 

The production silicon FB pin immediately ramps to 600mV and they are unable to alter the voltage.  Top side markings are:

BZR

82W

H7LR

 

Have there been any changes to the silicon or changes to the datasheet that we should be aware of?  The version of datasheet we are working from is September 2008.

 

Thanks~!!!

Dale

 

 

  • 0
    TI__Guru**** 165986 points

    No changes to the silicon or datasheet have been made.  The default voltage should be 200mV.   Do all of the ICs with that marking have this problem?

    If the customer has some extra ICs remaining, can they send a few to me?

    Jeff Falin

    Texas Instruments

    12500 TI BLVD MS8709

    Dallas, TX 75243

    214-480-2212.

    If they have the equipment, they might try, very carefully, removing a "bad" IC from their system and put it on EVM and see if it does the same thing. 

     

  • 0 in reply to Jeff F
    TI__Guru**** 165986 points

    After a failure analysis was performed on the returned ICs, it was determined that this lot of ICs was misprocessed.   Replacements were shipped. 

  • 0 in reply to Jeff F
    Prodigy 70 points

    So what we are talking about here is, unless I can prove the chips are at fault, I am own my own?
    Thanks,

    David