In this tutorial we are going to learn about HOW TO DECIDE LAYER IN PCB DESIGN ?
Many times, the number of board layers already has been determined by system constraints. If the PCB designer have authority , however, there are some guidelines.Very simple analog electronics are sometimes design on single sided PCB’s, keeping the raw board material inexpensive (FR-1/FR-2) with thin copper cladding. These designs frequently include many jumper wires then should be simulating the circuit routing on a double-sided board. susceptible to radiated noise. Therefore, it is actually more complex to design a board of this type due to the many things that can go wrong. The next level of complexity is double sided. Initially, Doble sided pcb design routing lend itself to easier routing, because now there are 2 layers of foil, & its possible to route signals by crossing traces on different layers. While that is certainly possible, its not recommended for analog circuitry. Wherever possible, the bottom layer should be devoted to a continuous GND plane, and all other signals routed on the top layer. A ground plane provides several benefits:
GND is frequently the most common connection in the circuit. Having it continuous on the bottom layer always use the most sense for circuit routing
It increases mechanical strength of the board.
It lowers the impedance of all GND connections in the circuit, which reduces undesirable conducted noise.
· It adds a distributed capacitance to every net in the circuit – helping to suppress radiated noise.
· It acts a shield to radiated noise coming from underneath the board.
Double-sided boards, have many benefit but have some issue in constructed , especially for
sensitive or high-speed designs. The most common board thickness is 1.5 mm.
. Distributed capacitance, for example, is
very low due to the separation. Critical designs call for multi-layer boards. Although more expensive,
they provide the following benefits:
· for Better PCB design routing for power as well as ground connections. Try to make If the power is also on a plane, If possible to all points in the circuit simply by adding vias.
· Remaining layer are available for signal routing, making routing easier.
· There will be distributed capacitance between the PWR & GND planes, reducing HF noise.
The decision to use multilayer boards is a complex one, balancing PCB cost with performance. Be sure to
consider the cost of qualification testing, if any. Multi-layer boards present much lower design risk.