Forums

STR912 RTC Crystal

Started by amerdsp January 31, 2008
Hello,
  I am trying to use a surface mount crystal for the RTC clock on the
STR912F microcontroller.  The datasheet states that the load
capacitance is 8pF (Typ).  Unfortunately, I am unable to find an SMD
crystal with that load capacitance.  I can, however, find 7pF and
9pF.  Can they be used?  Any hints or ideas?

Thank you,

A
amerdsp wrote:
> Hello, > I am trying to use a surface mount crystal for the RTC clock on the > STR912F microcontroller. The datasheet states that the load > capacitance is 8pF (Typ). Unfortunately, I am unable to find an SMD > crystal with that load capacitance. I can, however, find 7pF and > 9pF. Can they be used? Any hints or ideas? > > Thank you, > > A
No, Yes. Look at other crystals! -- Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED) ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk [at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL:
Your not just mating the XTAL to the CPU. The traces in between add
several pF of capacitance as well. So find an XTAL with 10-12pF
(12.5pF is common).

Eric