• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 62 subscribers
  • Views 895 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.

Application of CSD18536KTT

Mathew Locoteta
Prodigy 200 points
Other Parts Discussed in Thread: DRV8701, CSD18536KTT, CSD18536KCS

Hi,

I'm relatively new to this and haven't had the opportunity to take a class on MOSFETs just yet (soon!).  I've done some research and hopefully I'm not horrifically off on this.

I'm attempting to design a motor driver using the DRV8701 in conjunction with CSD18536KTT for the N-Channel FETs.  

My requirements are for a 24VDC Brushed Motor, rated at 24 Amps.  Locked rotor I measured it to be about 30-35 amps continuous.  The power supply I'm working with is rectified 24VAC, which ends up being around 33 VDC.   This will be controlled through PWM as well. 

These FETs might be overkill with respect to the continuous drain, but the other specs seem to be good.  Is there a problem with me being way over the top of the Id?   These FETs also have a very low Rds which is what I believe I should be looking for.  

Any suggestions, help or advice is much appreciated!

www.ti.com/.../csd18536ktt.pdf

Thank you,

Mat

  • 0
    TI__Mastermind 18200 points

    Mat,

    I actually wrote a blog about FET current ratings on datasheets and how they are basically bogus. If you want to learn a bit more about FETs or at least what their datasheet specs actually imply, you might want to check out the entire series. But here is the entry on current ratings:

    Having said that, this part should work well with the DRV8701. It is ultra low Rdson (actually the lowest Rdson 60V TO-220 in the world) which may or may not be overkill for your application. 

    It really depends on your thermal environment and how well your board pulls heat away from the FET. 

    Long story short, the CSD18536KCS is definitely the right FET to start with if you want a TO-220 solution. If you find that your board is running with no thermal issues, you can always swap out the CSD18536KCS with a higher Rdson, lower cost solution. 

  • 0 in reply to Brett Barr1
    Prodigy 200 points

    Hi Brett,

    I was actually watching your lectures about the MOSFETs just now and they have been very helpful. I'm almost done with the second presentation then I will read the rest of the material. I'm very impressed with how thorough the material is and thankful that it exists.

    I will test using this FET at first and see how well it performs!

    Thank you and much appreciated.
    -Mat

    Edit: Grammer