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USB 5VDC specs

Discussion in 'Electronic Design' started by M. Smile, Aug 2, 2005.

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  1. M. Smile

    M. Smile Guest

    Hi,

    anyone knows the 5VDC tolerance provided from a PC USB 1.1 connection?
    I can't find much details with Google.

    M.S.
     
  2. PeteS

    PeteS Guest

    From the USB specification:

    7.2.2 Voltage Drop Budget

    The voltage drop budget is determined from the following:

    · The voltage supplied by high-powered hub ports is 4.75 V to 5.25 V.

    · The voltage supplied by low-powered hub ports is 4.4 V to 5.25 V.

    · Bus-powered hubs can have a maximum drop of 350 mV from their cable
    plug (where they attach to a source of power) to their output port
    connectors (where they supply power).

    · The maximum voltage drop (for detachable cables) between the
    A-series plug and B-series plug on VBUS is 125 mV (VBUSD).

    · The maximum voltage drop for all cables between upstream and
    downstream on GND is 125 mV (VGNDD).

    · All hubs and functions must be able to provide configuration
    information with as little as 4.40 V at the connector end of their
    upstream cables. Only low-power functions need to be operational with
    this minimum voltage.

    · Functions drawing more than one unit load must operate with a 4.75
    V minimum input voltage at the connector end of their upstream cables.

    You can download the USB spec at :
    http://www.usb.org/home

    Cheers

    PeteS
     
  3. M. Smile

    M. Smile Guest

    Thanks for the info!

    M.S.

    7.2.2 Voltage Drop Budget

    The voltage drop budget is determined from the following:

    · The voltage supplied by high-powered hub ports is 4.75 V to 5.25 V.

    · The voltage supplied by low-powered hub ports is 4.4 V to 5.25 V.

    · Bus-powered hubs can have a maximum drop of 350 mV from their cable
    plug (where they attach to a source of power) to their output port
    connectors (where they supply power).

    · The maximum voltage drop (for detachable cables) between the
    A-series plug and B-series plug on VBUS is 125 mV (VBUSD).

    · The maximum voltage drop for all cables between upstream and
    downstream on GND is 125 mV (VGNDD).

    · All hubs and functions must be able to provide configuration
    information with as little as 4.40 V at the connector end of their
    upstream cables. Only low-power functions need to be operational with
    this minimum voltage.

    · Functions drawing more than one unit load must operate with a 4.75
    V minimum input voltage at the connector end of their upstream cables.

    You can download the USB spec at :
    http://www.usb.org/home

    Cheers

    PeteS
     
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