• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 63 subscribers
  • Views 341 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.

LM5140-Q1: Diode on the switching node

Sunset
Genius 14175 points

Part Number: LM5140-Q1
Other Parts Discussed in Thread: LM5143-Q1, CSD18543Q3A, CSD18563Q5A

Hello Team,

customer want to do remove some components:

The snubber network (R10 and C10) is for reducing the ringing on switching node, and I would let the customer keep it, just in case they need it. (but no need to assemble)

For the diode, they want to remove it, but it looks to be a protection to avoid that spikes or ringing may turn on Q1 body diode instead.

Can you confirm the needs of the diode below?

thanks,

SunSet

  • 0
    TI__Guru* 87517 points

    Hello,

    Yes, the anti-parallel diode can be removed as it hardly conducts during the deadtime. Just ensure that the low-side FET has a low Qrr. Take a look at the LM5143-Q1 EVM for a similar design where the diode is not used.

    Regards,

    Tim

  • 0 in reply to Timothy Hegarty
    TI__Genius 14175 points

    Thanks Tim,

    by remaining on TI MOSFET, is the CSD18543Q3A good enough to avoid D3?

    Would you recommend other NexFET?

    Or by using the CSD18543Q3A  would be a must to have?

    LM5143-Q1 looks to have other MOSFET...

    Thanks

    SunSet

  • +1 in reply to Sunset
    TI__Guru* 87517 points

    The LM5143-Q1 is a Q-grade controller, so it normally uses AEC-Q101 MOSFETs for automotive applications. However, NexFETs are fine for commercial grade applications. Depending on the output current and switching frequency requirements, it's better to use 5 x 6mm package MOSFETs for improved thermal performance - for example the CSD18563Q5A. Just ensure that the Rdson is rated for Vgs = 4.5V as the gate drive amplitude of the LM5143-Q1 is 5V.

    Regards,

    Tim