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TPS40055: TPS40055 VS TPS40051

Part Number: TPS40055
Other Parts Discussed in Thread: TPS40051

Hi.

We put on a board a TPS40051 to replace a TPS40055. The two components are very similary and we use the design example (fig 16 from the datasheet of the TPS40055).

In this case, all TPS are destroy and the mos connected to HDRV pin too.

If i compare the two design exemple (TP40055 VS TPS40051), we don't have the diode D2 connected to the SW pin. If this diode is missing, the TPS40051 is destroyed ?

Thank for your answer.

  • Hello Dominique 

    At first, I'd like to let you know TPS40051 is NRND device. 

    TI recommends customers to follow the application guidelines in the datasheet. We haven't validated the device works properly or not without the diode at SW. 

    -EL 

  • Thanks for choosing TI. Please feel free to contact us if you have any question.
    -EL

  • Our EMS found enough TPS40055 and repare all thes boards.

    You can close the subjet if you want... But you don't answer at my question!

    The initial subjet isn't the statut of the production of the TPS40051. We want to know why with the two parts have the same simplified schema , the same reference design in the datasheet (the only difference is the D2 diode in the TPS40051 reference design) with the same component (we use this design in our product) and it's dont work.

    You answer to me we don't test the component without the diode... what is the fonction of this diode dans if this diode is missing, what's happen ?
    i think i never know the answer.

    Dominique

  • Hello Dominique 

    Usually the diode populated between SW and GND is used to prevent an excessive negative voltage transient / to prevent a malfunction can happen due to this excessive negative voltage transient, but I am not sure this is the reason why TPS40055 requires the SW diode. Thanks for choosing TI. Please feel free to contact us if you have any question.
    -EL