2-Decoupling Capacitor
Every chip relies on a power supply to function. However, what if the power source is located at a distance from the chip? In such instances, the chip must draw power through the circuit board traces, typically via the PCB power layer. Placing the decoupling capacitor in close proximity to the chip’s power pin is crucial to mitigate the adverse effects of high-frequency noise. In cases where a chip features multiple VDD pins, each pin necessitates at least one decoupling capacitor, sometimes more. It’s imperative that these decoupling capacitors are physically situated very close to their corresponding pins for effective decoupling. Failure to do so significantly diminishes their efficacy. If your PCB design neglects to position decoupling capacitors adjacent to the power pins of most microchips, it indicates an incomplete design. If you’ve entrusted PCB design to a professional who mishandled decoupling capacitors, consider seeking alternative expertise.
3-Balancing PCB Trace Lengths
In designs requiring precise timing alignment among multiple signals, the lengths of PCB traces must be uniform. This is particularly critical when routing high-speed clock signals to multiple chips or data and address buses linking a microprocessor to RAM. Uniform trace lengths ensure that all signals reach their destinations with consistent delay, thereby preserving signal edge relationships. Achieving this necessitates referring to the schematic to identify signal lines requiring precise timing alignment and subsequently verifying trace lengths to ascertain if equalization (via delay lines) has been achieved.
It’s important to note that vias in the signal path introduce additional delay. If these issues are unavoidable, scrutinize all traces requiring precise timing alignment and ensure they incorporate an equal number of vias. Alternatively, utilize delay lines to compensate for via-induced delays.
Every chip relies on a power supply to function. However, what if the power source is located at a distance from the chip? In such instances, the chip must draw power through the circuit board traces, typically via the PCB power layer. Placing the decoupling capacitor in close proximity to the chip’s power pin is crucial to mitigate the adverse effects of high-frequency noise. In cases where a chip features multiple VDD pins, each pin necessitates at least one decoupling capacitor, sometimes more. It’s imperative that these decoupling capacitors are physically situated very close to their corresponding pins for effective decoupling. Failure to do so significantly diminishes their efficacy. If your PCB design neglects to position decoupling capacitors adjacent to the power pins of most microchips, it indicates an incomplete design. If you’ve entrusted PCB design to a professional who mishandled decoupling capacitors, consider seeking alternative expertise.
3-Balancing PCB Trace Lengths
In designs requiring precise timing alignment among multiple signals, the lengths of PCB traces must be uniform. This is particularly critical when routing high-speed clock signals to multiple chips or data and address buses linking a microprocessor to RAM. Uniform trace lengths ensure that all signals reach their destinations with consistent delay, thereby preserving signal edge relationships. Achieving this necessitates referring to the schematic to identify signal lines requiring precise timing alignment and subsequently verifying trace lengths to ascertain if equalization (via delay lines) has been achieved.
It’s important to note that vias in the signal path introduce additional delay. If these issues are unavoidable, scrutinize all traces requiring precise timing alignment and ensure they incorporate an equal number of vias. Alternatively, utilize delay lines to compensate for via-induced delays.
