Durability / reliability impact by turning LT3494 on and off repeatedly

Hello, I have an application in which (for this current board spin, at least) it would be nice if we could turn our LT3494 regulator on and off periodically to conserve power.  Putting the circuit into spice indicates we need about 3000 microseconds for the regulator to turn on and get up to our operational voltage. 

General spec:

Vin: 3.8 to 4.2V

Vout: 27V

Iout: <1mA

An example of timing for this would be:

  1. Enable LT3494 for 19666 microseconds.  This includes the 3000 microseconds needed for getting up to 27V.
  2. Turn off via the shutdown pin for 5333 microseconds.  This is the minimum off time - we may make this longer, but wanted to post for the most severe use case.
  3. Repeat forever.  Battery life is in the 10 hour range, but the intended useful life of the device is one year.

I don't believe this to be normal operation for any voltage regulator, but I also don't know where to find reliability data for this use case.  Any help is appreciated.  Thanks!

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  • 0
    •  Analog Employees 
    on Feb 19, 2021 2:14 PM

    Hi,

    The use case is fine and should not have any issues lasting one year assuming the silicon temperature is not excessive. Testing should be done to verify it matches LTspice with the components they are using. May want to add 20% to 50% in time for margin.

    If conserving power is important, please look at the LT8410 or LT8410-1.

Reply
  • 0
    •  Analog Employees 
    on Feb 19, 2021 2:14 PM

    Hi,

    The use case is fine and should not have any issues lasting one year assuming the silicon temperature is not excessive. Testing should be done to verify it matches LTspice with the components they are using. May want to add 20% to 50% in time for margin.

    If conserving power is important, please look at the LT8410 or LT8410-1.

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