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UCC27517A-Q1: Output pulse width

na na78
Guru 16770 points
Part Number: UCC27517A-Q1

Hi

Our customer has question about UCC27517A-Q1.

First of all, please see the following.

- Inverting (Input pulse width = 11nsec, T=176nsec)

- Inverting (Input pulse width = 11nsec, T=330nsec)

1.
VDD=14.7V, Input valtage = 3.3V.
Is the input pulse width (~11nsec) acceptable?

Is there limitation for PWM speed?

2.
Is there possibility of the differences for output pulse width depending on the input duty, like these two images?
(Upper figure : Duty ~6%, Lower figure : Duty ~3%)

BestRegards

  • 0
    TI__Genius 9790 points
    Hi,

    Thanks for your interest in TI here. I've contacted the appropriate product group. You should hear from them soon.
  • 0
    TI__Intellectual 2805 points

    Hello na na78,


    Unfortunately, we do not characterize the minimum pulse width for this device.
    The variation in rising and falling propagation delays can cause the pulse-width distortion shown in your figures.

    What is the application that requires this narrow pulse width? Do the increased pulse widths of 12.5ns and 11.5ns exceed design constraints?

    regards,
    Mateo 

  • 0 in reply to Mateo Begue
    Guru 16770 points
    Hi Mateo

    Thank you for your reply.

    The usecase is to drive the ToF sensor's optical part, so distortion is unwanted.

    I asked our customer to increase the pulse width to around 30 nsec, however, the distortion has occurred.

    In addition, they need 11nsec the output pulse width at least. So it is difficult to increase pulse width.



    And I present additional information.

    The distortion doesn't occur in non-inverting input even if the pulse width is 11 nsec.

    The customer requires the result of both of inverting and non-inverting input.
    So, the distortion in the inverting input should be avoided.


    Do you have idea? What is your view?

    BestRegard
  • 0 in reply to na na78
    TI__Intellectual 2805 points

    Thank you for the additional information.

    When the input pulse width is very narrow such as the 11-ns, the prop width may have some distortion.

    How much tolerance can the customer live with based on the application requirement?

    Also, how much input pulse width variation does the customer have?

    Regards,
    Mateo