query on crystal replacements

[onoffman]

hi,

I am making an ARM9 board that needed the crystals as shown
1)
18.432Mhz pack:3.2x2.5 mm e.g. ABM8-18.432MHZ-B2-T

2)
25 Mhz pack :MM20SS e.g.ECS-.327-12.5-17-TR


3)
32.768Khz pack : 3.2x2.5 e.g.ABM8-25.000MHZ-B2-T

these were not available in local market and digikey etc costed 5-6 times more

My changes

>>I bought local crystals as shown
1)18.432Mhz pack thru hole **broken link removed**

used with : AT91rm9200 atmel arm9 chip

2) 25 Mhz http://uk.farnell.com/productimages/farnell/standard/GE2HC494HSMX06-40.jpg
used with : ethernet controller chip
3)32.768Khz
**broken link removed**
used with :AT91rm9200 atmel arm9 chip

>I can manage to stick the crystals with superglue to some part of pcb
and join small wires to smd pads.


Question is will the substitution work.
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[pranam77]

As you have got the same values of the required components, it should work. It doesnt matter how you fit it...Cheers

 

[karesz]

Hi onoffman,
be care, that you will nothing connect_dont make shorts_ to some other potencial trough the metal can!
K.

 

[onoffman]

pranam77, karesz

thank you ..
i have done lott board buiding, smd too
i wil not short or allow metal can to touch


But the original parts had 4 pins these have 2 ..
where to put the pf capacitors ?

 

[M!k]

But the original parts had 4 pins these have 2 ..
where to put the pf capacitors ?

Look at the datasheet of the 4 pin types: 2 pins are not connected, 2 pins are the crystal.

Connecting the 2 load caps to 2 pins of the crystal isn't too difficult

 

[onoffman]

M!k,


that was a great help ! I will do that!

 

[karesz]

...of the 4 pin types: 2 pins are not connected, 2 pins are the crystal...

Be care, they are some (newer) Xtals on the market, with top plate contacting to the told "not connected" pins _ or minimum to one of both.
Also, its possible, that the not Xtal pins are i.e. on GND, but the Xtal pins=so the capacitors are surly not on GND-they are guided to the IC...
K.