Printed Circuit Boards - PCB

---

PCB (Printed Circuit Board) Impedance control is a critical aspect in the design of high-speed digital circuits. Impedance is a measure of the opposition to the flow of electrical current and can affect the quality of signals transmitted through the circuit.

In order to control impedance, designers must consider the following factors:

• Trace width: The width of the trace affects the impedance of the circuit. A wider trace will have a lower impedance, while a narrower trace will have a higher impedance.

• Trace thickness: The thickness of the trace also affects impedance. A thicker trace will have a lower impedance, while a thinner trace will have a higher impedance.

• Trace spacing: The spacing between the traces also affects impedance. A smaller spacing between the traces will result in a higher impedance.

• Layer stack up: The number of layers in a circuit board and the placement of the ground and power planes affect impedance.

• Material selection: The type of material used in the circuit board, such as the dielectric constant, affects impedance.

By controlling these factors, PCB impedance can be optimized to ensure high-speed signal transmission and minimize signal loss or distortion.