Hello
I'm designing a 4-layers PCB for a high speed ADC/ FPGA.
there are many 0.8mm pitch connectors/LFCSP/0201/0402/0603/0805/1206/..... packages on the board.
the surface finish is ENIG.
I have seen some people set a solder mask free area around the pads.
what's the advantage of solder mask free area around a pad?
how much the suitable size should I set for such a PCB?
Thanks