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TLV733P: Using the TLV733P with a switch

MohammedAl-Amin
Intellectual 540 points
Part Number: TLV733P

Hello,

I have a question about the LDO can it be used to run a mechanical switch button to operate at a regulated voltage level?

The reason being is that I have a limited space (2mm x 2mm) and one of the PIO require voltage levels to be 1.8V.

The button would be pressed quite a few times a day (estimate about 200 times a day)

So the LDO would be switched on and off at least 200 times a day as well, would this be ok for this LDO or having the LDO switching on and off this many times would damage the chip?

I have put an image where the LDO will go

  • 0
    TI__Guru 55940 points
    We will respond on the next US business day.

    Very Respectfully,
    Ryan
  • 0 in reply to Ryan Eslinger
    TI__Guru 55940 points
    It looks like you are essentially planning to hot plug TLV733P. While this is not necessarily a bad thing, there are some things you will need to be aware of. Every time you close or open a switch, you will have a massive line transient. If this transient exceeds the operating voltage range of the LDO, you may damage TLV733P. You also will want to consider the line transient response (figures 23 and 24 in the datasheet) to ensure that your load will be able to handle the transient response of the LDO.

    Very Respectfully,
    Ryan
  • 0 in reply to Ryan Eslinger
    Intellectual 540 points

    Hello, 

    Thanks for the response as the power is delivered by battery via Li-Ion Rechargeable battery, I don't think the transient would be excessive.

    What would you think?

    Best regards

    Mo 

  • 0 in reply to MohammedAl-Amin
    TI__Guru 55940 points
    Hi Mo,

    I may not be understanding how you drew your block diagram. The way it is drawn it looks like you plan for the LDO IN pin to be connected through the switch to the battery. In this case, while the battery voltage would be expected to be stable, the voltage at the Vin pin will have a transient each time the switch closes and opens. The transient will be reduced by adding capacitance between the switch and the LDO; however, each time the switch closes, the capacitors will charge up to the battery voltage. Each time the switch opens, the capacitors will discharge.

    If you intend for the LDO IN pin to be connected directly to the battery voltage and are intending to drive the EN pin via the switch, you would not have the line transient.

    Very Respectfully,
    Ryan