• State TI Thinks Resolved
  • Locked Locked
  • Replies 1 reply
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 78 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.

Original question:

TPS7B6950EVM: Pd calculation issue

TPS7B69: 24V to 3.3V with Io=100mA , not suitable in aspect of Junction temperature?

Nithiyanantham Krishnasamy
Prodigy 100 points
Part Number: TPS7B69
Other Parts Discussed in Thread: TPS7B81-Q1

Hello, 

we are planning to use the part# TPS7B6933 , our supply voltage is 24V and load expecting around 100mA.

When we calculate the Junction temperature it comes around 445degC, Am i doing anything wrong in the calculation ? or this chip is NOT suitable for my application?

Vi =24V ; Vo =3.3V ; Io=0.1A

Pd = 0.1 *(24-3.3) = 2.07W ; Tambient = 25degC 

Tj = Ta + (Rja * Pd) = 25+(210*2.07) =445Degc. 

Please guide us

  • 0
    TI__Intellectual 1720 points

    Hey Nithiyanantham Kr,

    Your calculations are quite valid and it would be difficult to support 2.07W for SOT-23 package of TPS7B69. I would request you to move to larger leaded package or no-lead WSON package.

    Please review TPS7B81-Q1 device with RthJA number in range of 40C/W for KVU package.

    Here are the details for thermal numbers:

    Regards,
    Rohit Phogat