DFN COMPONENT PACKAGE

# DFN Component Package

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## 1. Overview

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).

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.

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).

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.

Figure 3. The 3D model of the DFN-6 component package.
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].

Figure 5. The 3D model of the DFN-8 component package.
Figure 6. The package dimensions of the DFN-8 component package.
Figure 7. The package dimensions of the DFN-8 component package with exposed thermal pad.
Figure 8. The recommended land pattern and thermal properties of the DFN-8 component package.
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.)

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

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

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

## Authors

### Geoffrey Hunter

Dude making stuff.