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TPS73533 Verification

John Yan
Prodigy 170 points
Other Parts Discussed in Thread: TPS735

Hello all,

I'm using the TPS735 to convert the 5V input from a microUSB input to 3.3V. Could someone verify whether the topology of our circuit is correct?

For background: BP_VCC_5V is the 5V input from another booster pack. D1 and D2 are two Schottky diodes to supply the voltage of whichever is higher, the 5V from the USB or the 5V from the board.

Also, a side question: I notice that there are two available packages for the TPS735: a DRB (8 pin one I'm using), and a DRV (6 pins). From the data sheet I can see the DRB has better thermal resistance. Is there any other differences about them that I should take into consideration?

Thanks,

John

  • 0
    TI__Intellectual 2530 points
    HiThe appropriate apps engineer has been contacted. Thanks.
  • 0
    TI__Mastermind 23196 points
    Your question will be moved to the appropriate forum and they can give you a more complete answer but generally speaking the thermal resistance is the only difference assuming space isn't a constraint. If you use the larger package it will run only slightly cooler and you could argue it might be a bit more reliable, this is a function of the load, board layout, and environment of your application. If you have the space, then I would suggest going with a bigger package. If not then it go with the smaller. The package thermal resistance is very close to each other.
  • 0 in reply to fhoude
    TI__Guru 55940 points
    Hi John,

    The above comments on the differences between the two packages are correct. Both packages will have the same performance for the electrical characteristic specs; however, if laid out properly, the DRB package will run slightly cooler. Multiple packages are commonly offered as a convenience to our customers; however, space and thermals are the key differences.

    As to your schematic:

    A capacitor on the NR pin should be limited to 0.01uF.

    A minimum of a 2.2uF capacitor is required on the output pin to assure stability.

    Very Respectfully,
    Ryan
  • 0 in reply to Ryan Eslinger
    TI__Prodigy 170 points
    Jennifer, fhoude, Ryan,

    Thank you all for helping confirm. Ryan I've made the suggested changes to the capacitors in the schematic.

    Best regards,
    John