QFP

Quad Flat Package (QFP) is a family of surface-mount integrated circuit packages with a flat rectangular body and leads arranged on four sides. The leads are typically gull-wing and extend outward from the body to connect to a printed circuit board. QFPs allow a relatively high pin count in a compact footprint and are commonly used for microcontrollers, logic devices, and memory ICs.

Variants and terminology include Plastic Quad Flat Package (PQFP) and Ceramic Quad Flat Package (CQFP) for the molded plastic and ceramic versions, respectively. Other common forms include Low-profile Quad Flat Package (LQFP), Thin Quad Flat Package (TQFP), and Shrink Quad Flat Package (SQFP). These variants differ mainly in thickness, lead pitch, and overall footprint while preserving the four-sided lead arrangement.

Design and construction: QFP bodies are made from plastic or ceramic, with a lead frame forming four sides of leads. Lead pitches typically range from several tenths of a millimeter to about a millimeter, and body sizes vary accordingly. The package is intended for surface-mount assembly using reflow soldering, with pads on the PCB aligned to the package leads.

Applications and considerations: QFPs are favored for medium-to-high pin-count ICs in consumer electronics, automotive, and industrial equipment due to their balance of footprint, cost, and solderability. They occupy more board area than some newer no-lead packages and can be more challenging to rework if damaged. Availability of specific lead counts and pitches influences PCB routing decisions and comparisons with alternatives such as QFN or BGA.

Notes: QFP is distinct from QFN (quad flat no-lead), which uses pads under the package rather than along the perimeter.