Signal integrity refers to the quality of the signal on the transmission path; as the density of PCB boards increases, signal integrity has become one of the issues that must be concerned in high-speed digital PCB design. So, what are the signal integrity problems of PCB boards?
1. Reflection
When the signal is transmitted on the transmission line, when the characteristic impedance of the transmission line on the high-speed PCB does not match the source impedance or load impedance of the signal, the signal will be reflected, causing the signal waveform to overshoot, undershoot and cause ringing. .
2. Crosstalk
In PCB, crosstalk refers to the undesired noise interference generated by electromagnetic energy on adjacent transmission lines through mutual capacitance and mutual inductance coupling when the signal propagates on the transmission line. It is the electromagnetic field caused by different structures in the same area. produced by the interaction. On the PCB, crosstalk is related to the length of the trace, the spacing of the signal lines, and the condition of the reference ground plane.
3. Signal delay and timing error
Signals are transmitted at a limited speed on the wires of the PCB, and there is a transmission delay between the signals sent from the driver to the receiver. Excessive signal delays or mismatched signal delays can lead to timing errors and malfunction of logic devices.
