Quad Flat No Leads Package
Quad Flat No Leads Package ( QFN ), also known as Micro Lead Frame ( MLF ), is a chip housing type for integrated circuits (IC)that iscommonly usedin electronics . The name includes different sizes of IC packages which are all soldered as surface-mounted components on circuit boards .
As an essential feature and in contrast to the similar Quad Flat Package (QFP), the electrical connections ( pins ) do not protrude laterally beyond the dimensions of the plastic coating , but are integrated flat into the underside of the housing in the form of non-tinned copper connections . As a result, the space required on the circuit board can be reduced and a higher packing density can be achieved.
General
QFN chip housings were developed by Amkor Technology , which sells them under the trade names Micro Lead Frame (MLF) and Micro Lead Package (MLP). Individual QFNs and their sizes are specified under the JEDEC MO-220 standard .
The pins are usually located on the four sides of the flat housing, in some variants only on two sides. Some designs have one or more metal surfaces on the inside, which serve to dissipate the heat loss . QFNs usually have eight to 200 pins, which are arranged in a pitch of 0.4 mm to 1 mm. The housing heights differ depending on the type and are usually in the range of 1 mm, the thinnest designs have housing thicknesses of 0.4 mm and are also referred to as VQFN ( Very Thin-QFN ).
The small design reduces parasitic inductances at the connections, which is particularly advantageous in high-frequency applications such as mobile radio .
variants
The housings are available under various, mostly manufacturer-specific, names. Typical names are:
- MLPQ ( Micro Leadframe Package Quad )
- MLPM ( Micro Leadframe Package Micro )
- MLPD ( Micro Leadframe Package Dual )
- DRMLF ( Dual Row Micro Leadframe Package )
- DFN ( Dual Flat No-lead Package )
- TDFN ( Thin Dual Flat No-lead Package )
- UTDFN ( Ultra Thin Dual Flat No-lead Package )
- XDFN ( eXtreme thin Dual Flat No-lead Package )
- QFN ( Quad Flat No-lead Package )
- QFN-TEP ( Quad Flat No-lead package with Top Exposed Pad )
- TQFN ( Thin Quad Flat No-lead Package )
- VQFN ( Very Thin Quad Flat No Leads Package )
- DHVQFN ( Dual in-line compatible thermal enhanced very thin quad flat package with no leads (NXP) )
- UFQFPN ( Ultra thin Fine pitch Quad Flat Package No-leads (ST) )
Web links, sources
- Board Mounting Notes for Quad Flat-Pack No-Lead Package (QFN) (PDF; 42 kB), Application Note OnSemi, August 2002 - (AND8086 / D) (Engl.)
- Quad Flat Pack No-Lead (QFN) (PDF; 4.7 MB), application note Freescale Semiconductor, September 2008 - (AN1902) (Engl.)