Definition

IPC Classes define PCB quality and reliability requirements. Class 1: general electronics, limited life (disposables, toys). Class 2: dedicated service electronics, extended life (computers, telecom) - most commercial products. Class 3: high reliability, continued performance critical (medical, aerospace, military). Higher classes require tighter tolerances: better annular rings, plating uniformity, cleanliness, and documentation. Class 3 boards cost 20-50% more than Class 2 due to inspection, testing, and yield loss. Specify Class in fabrication notes. Class 2 is default; specify Class 3 only when reliability requirements demand it.