Frequency synth 113MHz

[meerweten]

i've been designing a 113MHz to demodulate a signal.
any thoughts on the design?

Some info:
i'm using a CDCE706/CDCE906 for generating the fequencies (up to 6 channels, only 3 used in my design) controlled using a pic16f628a (including a level shifter of mosfets)
in my old board i couldn't program the PIc as i would destroy the CDCE...
the frequency will be controllable using the 3 buttons i place on to it.

3DViews:



Top Layer:


Bottom layer:



a 3d pdf:
http://greendigit.be/Projects/Synth/PCB-9006-R1%20PCB3D.PDF
Normal pdf:
http://greendigit.be/Projects/Synth/PCB-9006-R1.PDF

[janoc]

I would have probably chosen a different PIC/processor that doesn't require 5V programming voltages. That would have allowed you to run the entire design on 3.3V and save all that level conversion.

Coincidentally I have just built a similar synthesis for my radio using Si5351a - there I am using an ATMega328 (wanted it to be Arduino-compatible because a lot of HAMs are not very microcontroller savvy) running directly at 3.3V and programmed either using 3.3V ISP programming or using serial bootloader. No level conversion needed.

[daqq]

Remove the thermal relief on the vias.

You are routing the crystal lines close to one of the outputs. Probably not an issue, but I'd avoid it.

As was said, dump the level conversion in favor of a CPU that can do 3.3V logic directly.

You can use some of the programming pins as the GPIO for the buttons. You save on GPIOs and routing.

Any reason to use 0805 caps for the crystal and 0603 everywhere else?

(If P1 is the power connector) Use a real power connector or something that you can more easily connect to.

[KJDS]

Some of the ground plane extends a long way from a grounding via, thus making it look more like an antenna than ground.

[sean0118]

Remove the thermal relief on the vias.

If your using Altium, in the rules for Polygon Connect Style you can use the queries IsVia and IsPad to setup two separate rules. 



Also, you have silkscreen on your pads, the anode 'A' for the leds and 'U2'.

[meerweten]

Any reason to use 0805 caps for the crystal and 0603 everywhere else?

simply cuz i don't have caps in 0603 that small a 'size', 10n is lowest i got 0603

Some of the ground plane extends a long way from a grounding via, thus making it look more like an antenna than ground.

darn didn't see that :p thanks

i've been thinking about a other uc too, but i still have loads of the 628a around so jhe :p

Remove the thermal relief on the vias.

If your using Altium, in the rules for Polygon Connect Style you can use the queries IsVia and IsPad to setup two separate rules. 



Also, you have silkscreen on your pads, the anode 'A' for the leds and 'U2'.

don't realy mind the silk there, ok it isn't nice looking but hell :p i don't wanne make my board larger there.
thanks for the tips on altium.
 


Edit: edited the layout. thanks for the input