PCB design software is the software in which engineers lay out a printed circuit board, or PCB: the flat board onto which chips and other parts are soldered and wired together. A PCB is usually green. It is made of layers of fibreglass with thin copper tracks between them. The tracks are the wires that carry power and signals from one part to another.
PCB design is separate from chip design. Chip design software, called electronic design automation (EDA), deals with billions of transistors inside one chip. PCB software deals with tens or hundreds of finished parts on one board. So the tools are simpler and cheaper, and many small companies and students use them.
The work has two steps. First, the engineer draws a schematic. A schematic is a diagram of the circuit, with each part shown as a symbol and each connection as a line. Second, the engineer does the layout. The software shows the board at its real size. The engineer places each part and then draws the copper tracks between their pins, the small metal legs or pads through which a chip connects to the board. The software checks rules while the engineer works. Tracks must be far enough apart, wide enough for their current, and placed where the board maker can make them.
Here is a typical case. An electronics company in Noida is designing the board for a UPI soundbox, the small speaker at a shop counter that announces each payment aloud. The board holds a microcontroller (MCU), a small computer on one chip. It also holds a 4G module, an audio amplifier, a battery charger and about 120 small parts. It must fit inside a box the size of a coffee mug. The engineer chooses a four-layer board, 60 mm by 50 mm. The two inner layers carry power and ground. The track between the 4G module and its antenna is kept short and of a fixed width, because radio signals weaken on long or uneven tracks. The software flags 14 places where tracks are too close together, and the engineer fixes them.
The software then produces the manufacturing files. Gerber files describe each copper layer, and a drill file gives the position of every hole. A bill of materials lists every part to buy. The files go to a board maker. The finished boards go to an assembly line, where machines place and solder the parts. The company orders 10 sample boards first, and tests them before it orders 50,000.
Fast signals and heat need more than rules. So the engineer checks the 4G section and the charger in signal and thermal simulation before the samples are made. Banks and payment companies give these soundboxes to shops, to sit beside the shop's UPI QR code.