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CSD95472Q5MC: VIN voltage overshoots

Ivy Hu
Prodigy 10 points
Part Number: CSD95472Q5MC
Other Parts Discussed in Thread: CSD95372AQ5M

in the datasheet of CSD95472Q5MC, it shows the remark as below. Just want to know why the high VIN can create excessive AC voltage overshoots? What's value of the "high" VIN? The recommended VIN is upto 16V, is the 16V high VIN?

Also i didnt see the similar remarks in other datasheet, like csd95372aq5m.  Is the AC voltage overshoots the common issues for the power stage product?

------------------------------------------------refer to datasheet----------------------------------------------------------------------------------------------------------

(1) Operating at high VIN can create excessive AC voltage overshoots on the switch node (VSW) during MOSFET switching transients. For
reliable operation, the switch node (VSW) to ground voltage must remain at or below the Absolute Maximum Ratings.

  • 0
    TI__Mastermind 18200 points

    Ivy, 
    I've reached out to our apps team. Hope to have some feedback for you shortly. 

  • 0 in reply to Brett Barr1
    TI__Mastermind 18200 points
    Ivy, Sorry for the delayed response on this. This is what I heard from our apps team:

    "The amount of AC ringing seen on the switch node of the device is highly dependent on the application and conditions.

    For hard switched buck converters it is proportional to the input voltage (VIN). The note is there to emphasize that the ringing on the switch node must be controlled (for example, through proper circuit layout, snubber design, etc.) as the input voltage increases.

    The switch node ringing should be checked in the actual design regardless of input voltage to ensure a robust design, but as a rule of thumb, anything over 13.2V is probably “high” for the CSD95472Q5MC and precautions should be taken to control the ringing. As long as the ringing is properly controlled, the device can be operated up to the maximum 16V.

    The reason for this note appearing in this datasheet but not the CSD95372AQ5M is that the breakdown voltage of the MOSFETs is lower and so it is more important that the ringing be accounted for in the design."