Rigid PCB With OSP

A rigid FR-4 printed circuit board with Organic Solderability Preservative (OSP) finish. OSP coats exposed copper pads with a thin organic film that prevents oxidation prior to assembly while remaining easy for solder to displace during reflow. The finish is lead-free, RoHS-compliant, low-cost, and produces a perfectly flat copper surface with no nickel underlayer, which makes it preferable for fine-pitch SMT and impedance-controlled designs where any added metal stack-up would shift signal performance. OSP boards have a shorter shelf life than HASL or ENIG once the bag is opened and are sensitive to handling and humidity, but for high-volume single-reflow assemblies they offer the lowest cost per board with excellent solder joint formation. Typical uses include consumer electronics, IoT, industrial control, lighting modules, and audio boards.