• State TI Thinks Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 291 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

TL1963A-Q1: Die power dissipation

Carlo
Expert 7715 points
Part Number: TL1963A-Q1

Good day.

Our customer would like to know the die power dissipation for  TL1963AQKTTRQ1. In section 10.3 of the datasheet, there was an equation and computation for the power dissipated by the device. Is the 1.41 W the same with the die power dissipation?

Thank you in advance for your help.


Regards,

Carlo

  • 0
    TI__Genius 14245 points

    Hi Carlo, 

    Does the customer want to know what the maximum power dissipation can be for TL1963AQKTTRQ1 or do they want to calculate the power dissipation in their application? 

    The power dissipation for any LDO will be mostly determined by the application. That is because for LDOs Pd=(Vin-Vout)*Iout +Ignd*Vin. In most use cases the power dissipation caused by the ground current is much lower than the load current and so that equation can be simplified to Pd=(Vin-Vout)*Iout. In the example that is given in the section on Calculating Junction Temperature, the application is going from Vin=6V to Vout=3.3V with Iout=0.5A and so the power dissipation will be ~1.4W for that use case. 

    If they want to calculate the maximum power dissipation the LDO can sustain without going into thermal shutdown then that will depend on the ambient temperature and the thermal resistance which is heavily dependent on the  board layout. For more information on the effect of board layout on thermal resistance we recently released an App Note comparing the thermal resistance of various types of board layouts. 

  • 0 in reply to Kyle Van Renterghem
    TI__Expert 7715 points

    Hello Kyle,

    Thank you for your quick reply and detailed explanation.

    Since the power dissipation is dependent on the application, is it possible to know the power dissipation of the TL1963AQKTTRQ1 alone or the device itself?

    Regards,
    Carlo

  • 0 in reply to Carlo
    TI__Genius 14245 points

    Hey Carlo,

    The board is the heat sink for ICs so this is why the maximum power dissipation will be dependent on the board. But we can calculate a maximum power dissipation using the thermal resistance from the junction to the ambient air (Rja). The equation used to calculate the junction temperature is Tj=Ta+Pd*Rja but we can use that to calculate the power dissiopation instead using Pd=(Tj-Ta)/Rja. for Tj we use 125C which is the maximum operating temperature the device is specified for, Rja is 22.8C/W and is found in the thermal table, Ta I'll assume to be room temp (25C). So the maximum power dissipation at room temperture is Pd=4.39W. 

    I hope that helps