Hi,
I use this IC in my personal project at the university. I would like to make a VFO with this IC for the shortwave band. I drive the PLL with a DDS, so I can get very little freq step without adjust big N and R.
The DDS freq range is 5MHz-5.8MHz. I can drive the PLL with differential sine wave (0.4Vp-p each), or a single ended square wave(0.5Vp-p). I can change it with solder elsewhere 2pcs 100n cap.
I made almost the basic recommended schematic.
When I start the circuit, the PLL works properly (so I think the MCU's code is good), but after a few minutes something goes wrong. Sometimes the OSCin module (or the controller section) goes wrong, and the output set on a fix freq (it can change when I change the output's div or vco div, but it's change independently from the input freq), or some output goes wrong, especially the LVPECL ones. I killed 5 ICs but I dont know where is the problem.
Please help me. I include the schematic and the pcb plan in PDFs and eagle format.
Thanks for help,
Balint
Top layer:
https://dl.dropboxusercontent.com/u/97546412/pll/1.pdf
Bottom:
https://dl.dropboxusercontent.com/u/97546412/pll/2.pdf
All:
https://dl.dropboxusercontent.com/u/97546412/pll/3.pdf
Schematic:
https://dl.dropboxusercontent.com/u/97546412/pll/4.pdf
Eagle:
https://dl.dropboxusercontent.com/u/97546412/pll/untitled.brd
https://dl.dropboxusercontent.com/u/97546412/pll/untitled.sch
