[SI-LIST] Re: question about the pull-up resistors
- From: steve weir <weirsi@xxxxxxxxxx>
- To: zhao.dave@xxxxxxxxx, si-list@xxxxxxxxxxxxx
- Date: Tue, 12 Apr 2005 20:53:24 -0700
David, if the requirement is a direct Vcc connection then you are probably
dealing with a power pin and need to make the direct connection. If an
application note only suggests a direct connection for a logic input, that
suggestion, not requirement, is probably to save you cost and area for the
pull-up / pull-down resistor. Saving the resisotr is fine, if it doesn't
cause headaches for mfg. test by depriving them the ability to exercise the
pin.
Steve
At 09:30 AM 4/13/2005 +0800, david wrote:
>dear sir,
> In some datasheets, i saw this expression " connect the pin to
>the system power bus(vcc) directly". I'm so confused by these words.
>In my opinion, when the pin was pulled up, it should be connected to a
>pull-up resistor, then connected to the power plane. The function of
>the resistor was to limit the surge current at the beginning of
>charging the load capacitors. But at present, i can't be certain
>whether to use the resistor in my design or not.
> Expect for your answer.
>
>--=20
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