Crystal for DS1302 chip

hmlittle59

Hello All,

The spec. on the Parallax website shows a Load Capacitance of 12.5pf and I have one that has a 6pf Load Cap. How far and How fast would that through off the Clock?

Thanks

Howard

wass

You've got the correct xtal according to the manufacturer's data sheet:

http://datasheets.maxim-ic.com/en/ds/DS1302.pdf

-Katie

hmlittle59

Yes I know but the Parallax site shows 12.5.

Howard

Mike Green

Complicating this question is the fact that the capacitance of even short PCB traces is on the order of a few pF. You really need to be careful to mount the crystal right at the DS1302 pins as shown on the datasheet.

wass

Some DS RTC chips allow either a 6pf or a 12.5pf crystal, for example: http://coecsl.ece.illinois.edu/ge423/datasheets/DS17885-DS17887.pdf
Perhaps Parallax got confused on the spec of the DS1302.

-Katie

hmlittle59

Great!!!

Guest I'll set up a couple of test units and see what happens.....


Howard