The source of interference refers to the component, device or signal that generates the interference; the propagation path refers to the path or medium through which the interference propagates from the source of interference to the sensitive device. What are the measures to cut off the interference propagation path in PCB design?
1. Fully consider the impact of the power supply on the microcontroller. If the power supply is well done, more than half of the anti-interference of the entire circuit will be solved. Many single-chip microcomputers are very sensitive to power supply noise, and a filter circuit or voltage regulator should be added to the power supply of the single-chip microcomputer to reduce the interference of power supply noise on the single chip.
2. If the I/O port of the microcontroller is used to control noise devices such as motors, isolation should be added between the I/O port and the noise source.
3. Pay attention to the wiring of the crystal oscillator. The pins of the crystal oscillator and the single-chip microcomputer should be as close as possible, and the clock area should be isolated with the ground wire, and the shell of the crystal oscillator should be grounded and fixed.
4. The circuit board should be divided reasonably, and the interference sources (such as motors, relays) should be kept away from sensitive components (such as single-chip microcomputers) as much as possible.
5. Use the ground wire to isolate the digital area from the analo area. The digital ground and the analo ground should be separated, and finally connected to the power ground at one point.
6. The ground wires of the single-chip microcomputer and high-power devices should be grounded separately to reduce mutual interference. Place high-power components on the edge of the board as much as possible.
7. Use anti-interference components such as magnetic beads, magnetic rings, power filters, and shields in key places such as single-chip microcomputer/o ports, power lines, and circuit board connection lines, which can significantly improve the anti-interference performance of the circuit.
