Issue link: https://resources.pcb.cadence.com/i/1541046
18. Optimizing Regulator and Power Converter Current Loops Switching regulators (buck, boost, buck- boost, LDOs with high di/dt) and other power converters are major sources of EMI, voltage ripple, and power integrity problems if not laid out with careful attention to their high-frequency current loops. The most critical paths are those with rapidly changing current; typically the input cap to high-side switch (VIN-to-SW), switch to ground, and output filtering to load. Minimizing the loop area reduces radiated EMI, voltage spikes, and switching noise coupled into sensitive analog or digital circuitry. Ignoring these loops often results in failed EMI tests, unstable supply rails, or even power-up failures in system bring-up. When And Where To Apply Apply current loop optimization immediately after placing all fixed and critical parts (Tips 5–7) and during the initial placement of every switching regulator, LDO (Low Dropout regulator) , or power converter; especially for any IC that switches above a few hundred kHz or supplies digital logic, RF, or analog circuits. Example buck converter layout illustrating current loops