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UCD7242: MOSFET electrical parameters

Part Number: UCD7242
Other Parts Discussed in Thread: UCD74120, CSD86350Q5D

Could you please provide electrical parameters for the MOSFETs in the UCD7242? I need to calculate losses as a function of input voltage, output voltage, inductance and switching frequency. Thanks! 

  • Hi Thomas,

    We will check if we can find the parameter.

  • With a discrete design, knowledge of the individual component characteristics are required to properly size them for the given loading and efficiency requirements of the end application. Given that the UCD7242 is a monolithic device designed for a specific design application, the systems/application engineers likely felt that providing the efficiency and power loss curves for the most used operating conditions would provide information more readily relevant to the end user than the individual component characteristics. Monolithic designs by other manufacturers are also specified in a similar manner which I suspect provides some protection to their underlying process capabilities as well.

    Are the curves not specific to your individual application?

  • No, the curves in the UCD7242 datasheet do not include the specific operating point of interest to me (11 V input, 1.8V output, with a different inductor). That said, I could probably interpolate between datasheet curves and back out the information I need, though it would be a bit of a hassle. More importantly, I was actually a bit confused when I submitted this post; I meant to ask this question of the UCD74120, which we are also using in our application. The UCD74120 datasheet has no efficiency curves.  

  • Hi Thomas,

    Sorry for the late reply.
    We found Rds-on information as below. Unfortunately I don't find other parameters.
    high side: 17 mohm , low side: 7 mohm

  • Thomas,

    Please refer to the CSD86350q5d datasheet, the UCD74120 is a multi-chip device which uses the same mosfets as the CSD86350Q5D.

    The Rsdon of the UCD74120 is slightly different due to the packaging but the gate charge, etc. should be consistent.

    Qian's numbers above are for the UCD7242.

  • Thank you Brad! This is exactly what I was hoping for. Thanks so much!