• State Resolved
  • Locked Locked
  • Replies 4 replies
  • Subscribers 63 subscribers
  • Views 382 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.

TPSM365R3: Comparing TPSM365R3 and TPSM5601R5Hx

gustavo zarba
Expert 1120 points
Part Number: TPSM365R3

Hi best people!
Comparing the datasheets of the TPSM365R3 and TPSM5601R5Hx I see that there are no mentions on the Output Voltage Ripple of the TPSM365R3 and no mentions to the Input Voltage Ripple on the TPSM5601R5Hx.
Could somebody help me with those specs?

On the other hand, I compared the thermal specs and deducted (I am not good on this matter) that the TPSM5601R5Hx will be less hot than the TPSM365R3. But I am not really sure, because the temperature, as I understand, will be dependent on the final load.
I will be appying 48 V to 50 V to the input and getting 2.4 V 270 mA (max) at the output.
The TPSM365R3 is much smaller than the TPSM5601R5Hx, but if I will be forced to have a bigger copper surface or air circulation around the device, then it would be a problem.
Me I get some help on this too? I would like to choice the best option for me.

Actually I am handling a two layers board, Would you recommend a 4 layers board? Weight is also a concern on my design Disappointed

Thanks a ot and kind regards,

Gustavo

  • 0
    TI__Guru 72785 points

    Hello

    I think I would go with the TPSM560xx.

    There seems to be a lot of pertinent information in the data sheet.

    The output voltage ripple and power dissipation are in the typical curve section 

    of the data sheet.

    The input voltage ripple can only be approximated by the following formula:

    Vri ~ D*(1-D)*Iout/(Fs*Cin)

    Where D = Vout/Vin and Fs is the switching frequency.

    The curves give a power loss of about 1W at Vin = 50V.

    Then you can use equation #3 and figure 11-5 to estimate the needed copper area.

    For an ambient of 85C, you would need about 10 to 15 square cm of area to be safe.

    The more area the lower the device temperature.

    I have attached an application note that may help with your thermal design.

    Thanks

    3060.snva951.pdf

  • 0 in reply to Frank De Stasi
    Expert 1120 points

    Hello Frank,
    thank you very much for the answer.
    I will follow your advice and go for the TPSM5601.

    In the mean time I had make a try-out design for the the board with the TPSM365R3. I don't like the footprint of the device. It makes lay-out difficult, if one has to observe the rules for thermal dissipation and short distances to other components.

    So I am happy to hear about your preference :)

    Thanks for the document with Thermal Design Tips too.

    The Webench designer is also a big help. It gives me an IC junction temperature of ca. 80°C for a Power dissipation of around 1 W.

    Just to be sure: when we talk about the safe thermal dissipation area on the pcb, are we talking about a free area exclusively around the device, or are we talking about the whole pcb? I have an area of 30 x 120 mm for the total pcb, but they are several other devices on it.

    Thanks again!

    Gustavo
     

  • +1 in reply to gustavo zarba
    TI__Guru 72785 points

    Hello

    Yes, it requires some judgement to decide how much of the PCB area is effective for a heat sink.

    We have a very crude rule that the thermal footprint is about 18 times the device area.  

    Sometimes you need to "eye-ball" it.

    Thanks

  • 0 in reply to Frank De Stasi
    Expert 1120 points

    Hi Frank,
    well, I will give a try. If it is too hot, there will be always a solution.

    This will not be the only part producing heat on the product: The violinist paying it will also dissipate many watts. Maybe the bow arm can also be used to blow some air on the chips!

    For the time being let us close this.

    Thank you again for the valuable tips.
    Many greetings from (not hot) Germany,

    Gustavo