My PCB design for Cyclone II ep2c20F484;ep2c35F484

Now I will rework my desine (will put larger via holes in central GND block) and then will see if my designe will fit in 6,7 or 8 layers.

6 layer : 8 layer:

signal (gnd) signal (gnd)

gnd only gnd only

vcore (few signal) vcore (few signal)

signal (gnd) signal (gnd)

vcc (few signal) signal (gnd)

signal (gnd) vcc (few signal)

gnd only

signal (gnd)

As I will make les than 50 bords than this leyer count is wery important for me becose price gets significantly higher bay eatch leyer.

here is price comparison of 6,8 leyer bords in PCBCART.com bord size 65mmx75mm, if I make 50 bords then prices are:

6layer;

590$ (1bord 11.8$)

8layer:

862$ (1bord 17.2$)

the diference in price for 1 bord is 5.4 $ and for sutch money I could buy lot of EMI filters for propper grounding.

If I will make fewer bords then this price diference will grow betwen 6 and 8 layer bords. But in high volium production diference will decrease then ofcourse it is cheaper to make 8, 10,.. 14 layer bords without emi filters that reduces total bord cost!

I read some articles about EMI filters and found murata emi noise suppression filters and these chip ferrite beads (which isn't so expensive just 0.03$) could be solution if ground plane can't handle EMI. So I will leave place for these SMD chip emi filters.