Dear everyone,
I'm trying to design PLL (450MHz-600MHz) including VCXO (27MHz) LMX2330, VCO (450MHz-600MHz) and the buffer amplifier MAX2472 with the tuning voltage 0V-5V. The problem I have not solved in a week is that it doesn't lock at 550MHz. The parameters are set up for the N-counter and R-counter: 1100, 54 respectively, 500kHz compared freq. It always lock with noise in 450MHz (0V tuning) after loading the code. Before loading the code, the frequency improves to 460MHz, which depends on the time delay and then it leaps to 450MHz with noise..... Please help me check it.