What is a standard cell library?

A standard cell library contains pre-designed, pre-characterized logic cells (inverters, NAND, NOR, flip-flops, etc.) with fixed height and variable width. Each cell includes: Layout (transistors, routing), Timing models (delay, transition, constraints), Power models (dynamic, leakage), and Abstract views for place-and-route. Cells are characterized across PVT (Process, Voltage, Temperature) corners. Modern libraries have hundreds to thousands of cells with multiple drive strengths, threshold voltages, and functionality. Libraries are foundry-specific and technology-node-specific.