Hi all,

As far as I am aware, you are currently discussing how to improve LMS6002 PLL phase noise. Below are some inputs from my side which may help.

Apart from playing with PLL registers we have two additional options.

1. Use clean TCXCO which provides 4 times higher reference followed by divide by 4 to generate PLL reference clock. Recently, we experimented with 30.72*4 MHz TCXCO. Dividing its output by 4 before going into LMS chip we have got improvement of 6dB in phase noise plateau region.

2. Current PLL loop filter has been designed to cover the whole LMS frequency range hence using kind of mid value for Kvco. We can customize the loop filter for a particular band. To do that we need to know frequency range China Mobile is looking for and reference clock you want to use (26MHz, 26*4/4MHz, ...). Please note that PLL reference clock does not need to be the same as system clock i.e. we can also use 30.72MHz, 30.72*4/4MHz etc.

Best regards, Srdjan