quadflat

Quad flat package, often referred to as quadflat, is a family of surface-mount integrated circuit packages characterized by a flat rectangular body with leads on all four sides. The leads extend from the package edges as gull-wing contacts and are soldered to the PCB pads in a bottom surface-mount configuration. The four-sided lead frame enables relatively high I/O count in a compact footprint compared with through-hole DIP styles.

Variations include Plastic Quad Flat Pack (PQFP), Low-profile Quad Flat Package (LQFP), and Thin Quad Flat Package (TQFP). The term quadflat is sometimes used generically for these four-sided leaded packages, while each variant has its own height, pitch, and lead-count specifications.

Construction and mounting: made with plastic or ceramic bodies; leads are formed from a leadframe and attached to the body; assembled by surface-mount reflow soldering. Pin 1 is indicated by a notch or dot.

Characteristics: typical pin counts range from about 20 to 208 pins; body sizes span roughly 5x5 mm up to around 40x40 mm; lead pitch commonly 0.4–1.0 mm. Applications include microcontrollers, memory devices, and other integrated circuits used in consumer electronics.

Advantages and limitations: benefits include relatively high pin density and suitability for automated assembly; drawbacks include larger footprint and potential solder-bridging issues compared with more modern no-lead packages like QFN.

Related terms: QFP, PQFP, LQFP, TQFP, QFN.