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UCC28880: Alternative non-isolated switcher

Part Number: UCC28880
Other Parts Discussed in Thread: UCC28881, UCC28911, UCC28910

Hi guys,

I saw TI does not recommend UCC28880 for new design, I developed a board with this switcher for a costumer but they are not in mass production yet. So I want to change the board design before start production.

This switcher provide 5V with 30 mA maximum, to an external MCU. I use this switcher in high side buck topology.

My goal is to change as little as possible the board desing.

I found UCC28881 with the same footprint. What about this alternative ?

Are there other alternatives for non-isolated switcher, low cost and low component count ?

Thank you

  • Hello Michele,

    Thank you for your interest in the UCC28881.   This device is the best substitute for the UCC28880, which is NRND but still available although currently, supply is tight.

    Because the peak current limit of the UCC28881 is more than twice as high as in the UCC28880, operation may change if you simply drop in the UCC28881 without any other changes.  In particular, the inductor will be subject to much higher peak current so it must be re-evaluated to ensure that it won't saturate.  As a consequence of the higher peak current, some operation that may have been in CCM may change to DCM.  Also the switching frequency will be lower, because of more current per cycle which needs to average out to your 30mA load. Ripple voltage may also increase.

    I recommend that you use the UCC28881 Design Calculator Tool https://www.ti.com/lit/zip/sluc626 , and plug in your existing component values to determine whether any limitations are exceeded.  Then run another calculation as if you are doing a new design and determine optimal components values for your application using the UCC28881.  Then decide whether changing to some or all of the new parameters may be advantageous to your design.

    Regards,
    Ulrich

  • Hi, 

    thank you for your suggestion but due the unavailability and long lead time, there is another AC-DC converter that I could evaluate for my application ?

    Small footprint, low cost and low component count are must.

    Thank you

    Michele

  • Hi Michelle,

    There are two other parts that you may consider for your application: UCC28910 and UCC28911.
    These can be configured into a non-isolated high-side buck topology similar to that of the UCC28880/1, with some layout change.

    Here are links to a few reference designs.  They are higher power than your application, but the design principles are the same to scale to your application.  https://www.ti.com/tool/PMP4443  https://www.ti.com/tool/PMP10766  https://www.ti.com/tool/PMP21384 

    Perhaps one of these are suitable.

    Regards,
    Ulrich