Layout theory planning of PCB devices that beginners must know

PCB device layout is a very tricky thing, but if you master its principles, everything will become very simple. Here are some PCB device layout principles that are summarized daily. 1. The I/O driver should be as close as possible to the edge of the printed board and to the lead-out connector; 2． According to the reasonable division of electrical performance, it is generally divided into: digital circuit area (that is, afraid of interference and interference), analog circuit area (fear of interference), power drive area (interference source); 3. For high-quality components, the installation location and installation strength should be considered; heating components should be placed separately from temperature-sensitive components, and heat convection measures should be considered when necessary; 4. 4. 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, adjust the relative position between the functional blocks to make the connection between the functional blocks the most concise; The I/O drive device is as close as possible to the edge of the printed board and to the lead-out connector; 6． The clock generator (such as crystal oscillator or clock oscillator) should be as close as possible to the device that uses the clock; 7. A discharge diode (1N4148 is sufficient) should be added to the relay coil; 8． The layout requirements should be balanced, dense and orderly, not top-heavy or heavy. 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); when the board space is dense, one can also be added around several integrated circuits Tantalum capacitors.