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UCC27511: UCC27511DBV Power dissipation

GaryC
Intellectual 2615 points
Part Number: UCC27511
Other Parts Discussed in Thread: UCC27424

May I know what is the power dissipation for UCC27511DBV? I can't find it in datasheet.

BR, Gary 

  • 0
    TI__Prodigy 80 points

    Hello,

    Thank you for reaching out on E2E! 

    Power dissipation will vary depending on the components and operating conditions that you are using, therefore we do not provide a typical value in our datasheets. However, we do provide a way to calculate this value which is shown below.

    For reference these formulas can found in section 10.2.2.8 of the UCC27511 datasheet.

     PDiss = PDC + PSW , where PDC is negligible

    QG = Gate Charge (from FET datasheet)

    fSW = switching frequency

    ROFF = ROL

    RON (effective resistance of pull-up structure) = 2.7 * ROL

     

    The formula shown above should provide you with the answer that you are looking for. If you have any additional questions please feel free to reach out.

    I hope this helps!

    Thank you,

    Donaldo

  • 0 in reply to Donaldo Sanchez
    TI__Intellectual 2615 points

    Hi Donaldo,

    Please refer to below spec. Could you share the power dissipation for UCC27511DBV (SOT-23 package)? Thanks

    BR, Gary

  • 0 in reply to GaryC
    TI__Prodigy 80 points

    Hello,

    The UCC27511 does not specify a maximum power dissipation spec like the part mentioned above.  

    I have provided a table for UCC27511 that has the corresponding thermal information to help with your power dissipation calculation. The table can be found in section 8.4 of the datasheet if you would like to reference it.

    Feel free to post any additional questions that you have regarding this issue.

    Thanks,

    Donaldo

  • 0 in reply to Donaldo Sanchez
    TI__Intellectual 2615 points

    Hi Donaldo,

    We need a specific data as like UCC27424. Please help to calculate it, and show the data to us. This data will compare to actually Pd and know whether have enough margin in this design. 

    BR, Gary 

  • 0 in reply to GaryC
    TI__Genius 11145 points

    Hi Gary,

    Thank you for your reply!

    Our datasheet does not provide this information so I cannot give you a specific value as in the UCC27424 datasheet.

    I can give you an estimate, however it is not an official value and should only be used as an estimated reference value. It is not going to be fully accurate as many factors affect power dissipation. 

    Maximum power dissipation at ambient temperature 25°C for the UCC27511 can be estimated by taking our maximum recommended operating temperature of the device Tj (140 °C) minus the ambient temperature Ta (25°C) and dividing it by the junction-to-ambient thermal resistance ΘJA from the datasheet (217.8 °C/W). 

    PD = (Tj - Ta) / ΘJA

    PD = (140°C - 25°C)/(217.8 °C/W)

    PD = 528mW

    Thank you,

    Kevin