• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 64 subscribers
  • Views 728 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

LP5907-Q1: Drift over time questions

Viktorija Cecil
Mastermind 18311 points
Part Number: LP5907-Q1


Team, 

Can you please help address my customer's questions:

Part in question:

                LP5907QMFX-2.5Q1

Description

                Linear Regulater VIN = 5V, Vout = 2.5

Open questions

  • Does the linear regulator drift over time if input voltage is always somewhat nominal i.e. 5v?
  • Is it possible to drift above the outputted 2.5V?
  • Does the hypothetical drift always go lower than nominal voltage?
  • What is the minimum input voltage needed to obtain nominal output voltage?
    • Absolute maximum ratings says min is -0.3V ( I assume to not damage)
    • Recommended operating conditions Vmin is 2.2 (I assume this is the answer)
    • For automotive applications, the lifetime of our PCBA is 10 years.  Can I expect drift on this part if operation is constant?

 Thanks

Viktorija

  • 0
    TI__Genius 14245 points

    Hi Viktorija

    See my answers in blue:

    • Does the linear regulator drift over time if input voltage is always somewhat nominal i.e. 5v? In general since our LDOs are power management products and not reference voltages they are not specified to have a certain drift vs time and are usually used in applications where accuracy over all conditions is more important than the accuracy of an individual unit at any specific point (Temp, Vin, Iout, Time, etc...) therefore our tests are directed at overall accuracy and not an individual device's output voltage change from one point in time to another. 
    • Is it possible to drift above the outputted 2.5V? The output may drift slightly above the nominally set 2.5V due to temperature drift, but it shouldn't drift higher than the accuracy specified by the datasheet. 
    • Does the hypothetical drift always go lower than nominal voltage? If we are talking about temperature drift, the output will generally drift in a parabolic, y=-(x^2), manner. If we are talking about drift over time, this is not a standard test for LDOs so it is unknown how an individual device will change with time since we test to make sure that the output still meets the overall accuracy spec.  
    • What is the minimum input voltage needed to obtain nominal output voltage? In order for the LDO to regulate the output voltage the input voltage must be greater than or equal to the output voltage plus the dropout voltage for the application's load current (Vin>=Vout+Vdo). So For a nominal output voltage of 2.5V with a 250mA load current Vin>=2.75V. 
    • Absolute maximum ratings says min is -0.3V ( I assume to not damage) Yes, abs max ratings are specified with regard to avoiding damaging the device. 
    • Recommended operating conditions Vmin is 2.2 (I assume this is the answer) Vin(min), 2.2V for this device, is the point where the LDO starts to operate, however if the nominal output voltage is higher than Vin(min) then the LDO will be in dropout and the output will not be regulated until Vin>=Vout+Vdo. 
    • For automotive applications, the lifetime of our PCBA is 10 years.  Can I expect drift on this part if operation is constant? As mentioned above drift over time is not in a typical LDOs specification, though overall accuracy is tested after performing our long term reliability stress tests to make sure that the part still meets the accuracy spec in the EC table. 

    -Kyle