DFN COMPONENT PACKAGE

DFN Component Package

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1. Overview

Name

DFN (Dual Flat No-lead)

Synonyms

  • DFN (Linear Technology, Micron Technology Inc, this synonym is more common than the JEDEC named SON!)

  • DRP/S-PVSON-N6 (TI)

  • DSG/S-PWSON-N8 (TI)

  • LLP (Leadless Lead frame Package). The terminology used by National Semiconductor for their SON/DFN/QFN packages until they were acquired by Texas Instruments[1].

  • MLP (micro leadframe package or moulded leaded package). This also can refer to variants with pins on all four sides of the package, which is also called a QFN package). This name is used by Linear Technologies, Carsem.

  • MLPD (MLP dual).

  • MLPM (MLP micro). This name is used by Carsem.

  • MLPQ (MLP quad).

  • PE-SON-8 (SON-8, Ricoh)

  • SW-PWSON-N8 (SON-8, TI)

  • VDFPN (Numonyx, Micron Technology)

  • VFDFN (DigiKey, e.g. part TPS54260DRCT).

  • VSON (Texas Instruments)

  • WDFN-6 (SON-6, On Semiconductor/Fairchild Semiconductor)

Similar To

  • QFN (note that some may call SON a variant of QFN)

  • SOD-882 (two pad package used for diodes)

  • SOT-883 (three pad package used for transistors)

Variants

The SON package can have a varying number of pins. There are also VSON and WSON packages which are exactly the same as the SON package except for a different height. This package can also optionally include an exposed pad.

Mounting

SMD

Pin Count

4-20+ (depends on variant)

Pitch

Depends on variant.

Solderability

Reflow soldering is recommended. Hard to solder with a soldering iron due to underside thermal pad (some don’t have a thermal pad, and in that case, your chances are better). The tiny pitch is not so much of an issue as unlike the TQFP package, solder bridges are really easy to remove. You can solder the exposed pad in some cases by drilling a hole in the centre of the pad and soldering from the underside.

Thermal Resistance

Depends on variant.

Package LxWxH

Depends on variant.

Typical PCB Land Area

Depends on variant.

3D Models

n/a

Common Uses

  • MOSFETs

  • Embedded SIM cards

  • Solid-state load switches

  • Flash memory ICs

The DFN (Dual Flat No-lead) component package is also commonly known as the SON package. TI also calls this the Plastic Small Outline No-lead package.

The DFN package is very closely related to the QFN package. From what I can tell, the main difference between the DFN and QFN package is that the DFN package generally only has pins running down two of it’s sides, while a QFN package has pins on all four sides. However, this is not a hard-and-fast rule, for example the V-DFN3020-13 (Type A) package by Diodes Inc. has pins on three of four sides[2]. The other big difference I have seen is that QFN packages seem to more standardized with consistent pin/package shapes and dimensions, whilst packages labelled "DFN" can have all sorts of "weird" pad/package geometries (see Figure 1).

ap63356 dfn pin assignments
Figure 1. Outline of the V-DFN3020-13 package by Diodes Inc[2]. Notice the very un-standard pin geometries, which you’ll see in some DFN packages.

JEDEC standard JESD75-5 specifies how generic logic circuits will be connected to certain pins of the DFN package.

Below is an "odd shaped" SON package used by Numonyx flash chips that goes under the name VDFPN8. Notice the half-round appearance of the pins.

component package vdfpn8 mlp8 outline dimensions
Figure 2. Outline and dimensions for the VDFPN8 (SON-8) component package of a Numonyx flash IC.Image from http://www.micron.com/~/media/Documents/Products/Data%20Sheet/NOR%20Flash/Serial%20NOR/M25P/M25P128.pdf.

Texas Instruments AN-1187: Leadless Leadframe Package (LLP) is a great PCB designers reference document when using DFN or QFN packages (the document calls them LLP, but it is the same thing as DFN/QFN).

2. Thermal Pad

The SON package has a exposed thermal pad on the underside, similar to a QFN package.

For a comparable TQFP package with the same pin count, the SON package (with an exposed pad) can usually handle more than twice the power dissipation.

3. DFN-6, 3x3mm

The DFN-6 3x3mm package is used for components such as MOSFETs.

son 6 component package 3d model
Figure 3. The 3D model of the DFN-6 component package.
son 6 component package with two thermal pads
Figure 4. The 3D model of the DFN-6 component package which has two thermal pads instead of one.

4. DFN-8, 3x3mm

The DFN-8 3x3mm package is used for components such as linear regulators[3].

son 8 component package 3d model
Figure 5. The 3D model of the DFN-8 component package.
son 8 component package dimensions
Figure 6. The package dimensions of the DFN-8 component package.
son 8 component package exposed thermal pad
Figure 7. The package dimensions of the DFN-8 component package with exposed thermal pad.
son 8 component package land pattern and thermal properties
Figure 8. The recommended land pattern and thermal properties of the DFN-8 component package.
son 8 component package ti land pattern
Figure 9. The recommended land pattern (from TI) of the DFN-8 component package.

5. WSON And VSON Variants

The WSON and VSON variants of the SON package are identical to the SON package except for varying heights.

The WSON variant has a height of 0.80mm (max.)

wson component package height
Figure 10. An outline of the WSON component package showing it’s height.

The VSON variant has a height of 1.00mm (max.)

vson component package height
Figure 11. An outline of the VSON component package showing it’s height.

References

Authors

Geoffrey Hunter

Dude making stuff.

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This work is licensed under a Creative Commons Attribution 4.0 International License .

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