What’s LQFP?
Low Profile Quad Flat Pack (LQFP) is a surface-mount IC package with leads extending from all around four sides of the package body. QFP packages provide the same benefit of the metric TQFP packages with 1.4 mm body thickness (less than 1.7mm, but more than 1.2mm), but are thinner and have a standard lead-frame footprint (0.2mm). Pins are numbered counter-clockwise from the index dot. This package allows IC packaging engineers, component specifiers and systems designers to solve issues such as increasing board density, die shrink programs and thin end‑product profile.
Low Profile Quad Flat Pack
LQFPs help to solve issues, such as increasing board density, die shrink programs, thin end-product profile and portability. Lead counts range from 32 to 256. Body sizes range from 7×7 mm to 28 x28 mm. Copper lead-frames are used for this dummy component package. Lead pitches available for low profile quad flat pack package are 0.4mm, 0.5mm, 0.65mm, and 0.80mm. The typical body thickness is 1.4 mm.
| Properties of Some Examples | ||||
| Part Number | No. of Pins |
Body Size | Body Thickness | Lead Pitch |
| LQFP-48 | 48 | 7 x 7 mm | 1.4 mm | 0.5 mm |
| LQFP-64 | 64 | 7 x 7 mm | 1.4 mm | 0.4 mm |
| LQFP-100 | 100 | 14 x 14 mm | 1.4 mm | 0.5 mm |
| LQFP-128 | 128 | 14 x 14 mm | 1.4 mm | 0.4 mm |
| LQFP-128 | 128 | 14 x 20 mm | 1.4 mm | 0.5 mm |
| LQFP-144 | 144 | 20 x 20 mm | 1.4 mm | 0.5 mm |
| LQFP-216 | 216 | 24 x 24 mm | 1.4 mm | 0.4 mm |
| LQFP-256 | 256 | 24 x 24 mm | 1.4 mm | 0.4 mm |
This package requires a carefully designed PCB concerning electromagnetic compatibility. In additional to the PCB design guidelines in datasheet, which gives general design rule information for PCB design. Printed circuit board design and construction are key factors for achieving solder joints with high reliability. Packages with exposed pads should not be placed opposite to each other on either side of a PCB when doing double-sided mounting. This will stiffen the assembly and cause solder joints to fatigue earlier than in a design in which the components are offset. Furthermore, the board stiffness itself has a significant influence on the reliability of the solder joint interconnect if the system is used in critical temperature-cycling conditions.
LQFPs have an exposed die pad on the bottom of the package, which is created by an appropriate lead frame down-set. The exposed pads are usually soldered to the Printed Circuit Board (PCB) for mechanical, electrical and thermal connection.
See QFP, PQFP, CQFP and TQFP. Make your turnkey PCB assembly with components sourcing service at MADPCB.