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AM4372: Updated AM437x schematic checklist

Kanae
Mastermind 9635 points
Part Number: AM4372


Hi Sitara support Team,

Please let me know about the AM437x schematic checklist updated on Sep. 25, 2020.
www.ti.com/.../sprace0a.pdf

The Revision History shows the following, which is the exact opposite of the settings before the update.

==========================================================
Changes from Revision Initial (March 2019) to Revision A (September 2020)
- Changed 'For host operation, USB VBUS decoupling capacitance should be < 120 µF.' to 'For host operation,
USB VBUS decoupling capacitance should be >= 120 µF.
==========================================================

What is the impact of using 120uF or less as previously stated?

Best regards,
Kanae

  • 0
    TI__Mastermind 27720 points

    Hello Kanae,

    This change was made to correct a typographical error in the original version of the document. The USB specification requires that Host controllers provide at least 120uF of capacitance on the VBUS line to ensure that inrush current doesn't cause the voltage to droop below VBUS_VALID when attaching a USB Device. This is not a SoC specific requirement.

    Insufficient capacitance on VBUS could cause some USB Devices to fail to properly enumerate when initially connected.  

  • 0 in reply to -DK-
    Mastermind 9635 points

    Hi DK,

    Thank you for your reply.
    I will report this to my customer.

    If the customer has any additional questions,
    please continue to support us.

    Best regards,
    Kanae