• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 606 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS2819: Leaving Vdd pin floating

Sunset
Genius 13985 points
Part Number: TPS2819
Other Parts Discussed in Thread: TPS2829

Hello Team,

the TPS2819  and TPS2829 share the same datasheet and the difference is about the internal regulator.

pin 1 is NC on the TPS2829  while it is Vdd on TPS2819.

If we would use the TPS2819   instead of the TPS2829, but the PCB has pin 1 floating (it was designed for the TPS2829), thus not connected to Vcc as recommended for the TPS2819  in case Vdd is not used.

Do you see any problem by that exchange?

Can the part still work?

Considering the diode on top of the LDO, it looks that it may work, but how reliable would be?

The datasheet states that unused Vdd for the TPS2819 should be connected to Vcc, thus it will remain customer risk not connecting it.

The info above would help the risk analysis.

Thanks,

SunSet

  • 0
    TI__Genius 13445 points

    Hello,

    Thanks for reaching out.

    The VDD pin is output of the internal regulator which may be tied to VCC external when the regulator is not needed. 

    For your case, you may pull the pin high and externally tie it to VCC to short the regulator and accommodate the p2p compatibility.

    Leaving the pin floating may also be OK, the part would be functional according to the block diagram though depending on your application and expected board and system parasitic, the driver IC may be exposed to coupling through that pin that may present system challenges.

    Regards,

    -Mamadou 

  • 0 in reply to Mamadou Diallo
    TI__Genius 13985 points

    Hello Mamadou,

    thanks for the feedback.

    The PCB is already done.

    Vdd (pin 1) is IN not OUT.

    Is it your comment still valid:

    Leaving the pin floating may also be OK, the part would be functional according to the block diagram though depending on your application and expected board and system parasitic, the driver IC may be exposed to coupling through that pin that may present system challenges.

    Thanks,

    Mauro

  • +1 in reply to Sunset
    TI__Genius 13445 points

    Hello,

    For validation of few units you may get away with it but I would not recommend leaving functional pins floating for full production because of potential system's noise and parasitic coupling onto the supply pin.

    Regards,

    -Mamadou