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Original question:

UCC27532-Q1: UCC27532-Q1 for SiC FET: parallel use

UCC27531-Q1: part-to-part IN propagation delay mismatch

Helge Wurst
Prodigy 60 points
Part Number: UCC27531-Q1
Other Parts Discussed in Thread: UCC27531, UCC27532

UCC2753x series datasheets specify turn-on and turn-off propagation delays over -40 to +140°C temperature range.  However, it isn't immediately clear whether these are typical values over temperature or whether they also include part-to-part variations.

In our application, the devices are located next to each other and assumed to stay within +/- 5 K w.r.t. each other.

What equal temperature part-to-part propagation delays are typical for UCC27531 and UCC27532?

  • 0
    TI__Genius 13445 points

    Hello Helge,

    Thanks for reaching out.

    The image in your initial thread did not post, I assume you're referring to Figures 15 and 16 in the UCC27531 d/s.

    These are typical values based on specific test conditions and will vary according to load, gate drive voltage, etc... 

    Though these drivers are from the same family using similar processes, technologies and die I need to caution you about their respective VIN_H and VIN_L thresholds as the IC's have different thresholds which means if you're driving the IC's with similar signals UCC27531 (2V) will be turning on before the UCC27532 (9.4V). 

    Regards,

    -Mamadou

  • 0 in reply to Mamadou Diallo
    Prodigy 60 points

    Hello Mamadou,

    thank you for your fast response. To clarify, only one type of gate driver (e.g. UCC27532) will be used, with 2-4 of them in parallel with individual OUTH and OUTL resistors. The question pertains to device behavior when INs are tied together, and EN is used, for example, to adjust gate drive currents.

    with a part-to-part variation of for example 5-10 ns, the switching waveform would become less predicatable, which is undesirable.

  • 0 in reply to Helge Wurst
    TI__Guru**** 189399 points

    Hi, Helge,

    Our office is closed for a holiday weekend here in the US. Mamadou will get back with you early next week on this additional information.

    Have a nice weekend!

  • 0 in reply to Helge Wurst
    TI__Genius 13445 points

    Hi Helge,

    Thanks for clarifying.

    So long as you're using the same parts in parallel and that the PCB layout is (as) symmetrical (as possible), you should expect part-to-part variation of <=3ns given that the units use same process and technology.

    Please confirm if this addresses your inquiry.

    Regards,

    -Mamadou

  • 0 in reply to Mamadou Diallo
    Prodigy 60 points

    Thanks, that sounds promising and answers the question.