The general PCB layout is carried out according to the following principles:
(1) According to the reasonable division of electrical performance, it is generally divided into: digital circuit area (that is, fear of interference and interference), analog circuit area (fear of interference), and power drive area (interference source);
(2) Circuits that complete the same function should be placed as close as possible, and each component should be adjusted to ensure the most concise connection; at the same time, the relative position of each functional block should be adjusted to make the connection between the functional blocks the most concise;
(3) For components with large mass, the installation location and installation strength should be considered; heating components should be placed separately from temperature sensitive components, and heat convection measures should also be considered if necessary;
(4) The I/O drive device should be as close to the edge of the printed board as possible, and close to the lead-out connector;
(5) The clock generator (such as: crystal oscillator or clock oscillator) should be as close as possible to the device that uses the clock;
(6) Between the power input pin of each integrated circuit and the ground, a decoupling capacitor (generally a monolithic capacitor with good high-frequency performance is used); Add a tantalum capacitor around it.
(7) A discharge diode should be added to the relay coil (1N4148 is enough);
(8) The layout requirements should be balanced, dense and orderly, not top-heavy or heavy-headed