thumb|A [[Zilog Z80 in a 44-pin QFP (special case: LQFP)]]

A quad flat package (QFP) is a surface-mounted integrated circuit package with "gull wing" leads extending from each of the four sides. The QPF only became common in Europe and United States during the early nineties. It is often mixed with hole mounted, and sometimes socketed, components on the same printed circuit board (PCB).

A high package related to QFP is plastic leaded chip carrier (PLCC) which is similar but has pins with larger pitch, 1.27 mm (or 1/20 inch), curved up underneath a thicker body to simplify socketing (soldering is also possible). It is commonly used for NOR flash memories and other programmable components.

Limitations

The quad flat-pack has connections only around the periphery of the package. To increase the number of pins, the spacing was decreased from 50 mil (as found on small outline packages) to 20 and later 12 (1.27 mm, 0.51 mm and 0.30 mm respectively). However, this close lead spacing made solder bridges more likely and put higher demands on the soldering process and alignment of parts during assembly.

  • HVQFN Documentation at NXP Semiconductors
  • More about HQVFN
  • PQFP packaging information from Integrated Silicon Solution, Inc. (PDF)