by Spehro Pefhany <speffSNIP@[EMAIL PROTECTED]
>
Aug 9, 2008 at 10:59 AM
On Sat, 09 Aug 2008 19:32:53 +0530, the renowned ClueLess
<clueless@[EMAIL PROTECTED]
> wrote:
>For very slow crystals it is necessary to add a series resistance in the
crystal
>circuit. How do you calculate its value with respect to the two
capacitors that
>connect the crystal to the ground?
The resistor is there to limit drive power.. so it depends on crystal
characteristics (ESR, max drive power) and other things (drive
voltage, load caps). It's not a straightforward calculation,
particularly if you want to minimize power consumption and/or drive
power. Overdriving the crystal can lead to excessive drift or failure.
Typically 32kHz-ish crystals have *maximum* drive powers in the 1uW to
100nW range.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@[EMAIL PROTECTED]
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