When draw PCB, see some high-speed chip manual will write to the input and output ground plane need hollow out, avoid to produce the stray capacitance, makes the phase margin is reduced, the circuit is not stable, what reason is this? Why are these capacitance will make circuit unstable?
The second question is punched for performance will have impact on PCB? The input line punching?
For bosses to help answer ah

CodePudding user response:

1. The parasitic capacitance has great influence to the high frequency signal, because the impedance of the parasitic capacitance of the high frequency signal is relatively small, this is equivalent to the dc signal lines connected to a small resistance to the ground, the influence on signal amplitude is large, the impact on the high frequency ac signal is phase margin is reduced,
2. The high frequency circuit, must be in the input and output line both sides of the punch, and hole should neatly, hole spacing and signal lines between the frequency of the ac signal, specific can view the corresponding manuals, additional input line is short, as far as thick and straight,