Hi there,
After recently creating my own board for the LMX2581, I am getting terrible spurs at Fosc offset. Using a 50MHz crystal, seeing spurs at 50, 100, 150 MHz away at -40dB down from main wanted signal.
Any idea on how to suppress these?
Many thanks
Hopefully you can see that.
Register settings.
R15 0x021FE80F
R13 0x4082C10D
R10 0x210050CA
R9 0x03C7C039
R8 0x207DDBF8
R7 0x00082317
R6 0x000004C6
R5 0x0030E005
R4 0x00000004
R3 0x200CF423
R2 0x0FD09002
R1 0x95B72021
R0 0x4040E800
Hi Callum,
According to your register setting, I've got the following configuration.
In below, the VCO frequency is not correct, is your fpd = 25MHz?
if your reference clock is 50MHz, then OSC_FREQ should be =0.
Channel B is not use, our recommendation is to have the OUTB_MUX set to equal to OUTA_MUX.
You have a T-pad after the XO, could you remove it to see if there is improvement in spurs?
