NTD4302
INFORMATION FOR USING THE DPAK SURFACE MOUNT PACKAGE
RECOMMENDED FOOTPRINT FOR SURFACE MOUNTED APPLICATIONS
Surface mount board layout is a critical portion of the
total design. The footprint for the semiconductor packages
must be the correct size to ensure proper solder connection
6.20
0.244
interface between the board and the package. With the
correct pad geometry, the packages will self align when
subjected to a solder reflow process.
3.0
0.118
2.58
0.101
5.80
0.228
1.6
0.063
6.172
0.243
SCALE 3:1
mm
inches
SOLDER STENCIL GUIDELINES
Prior to placing surface mount components onto a printed
circuit board, solder paste must be applied to the pads.
Solder stencils are used to screen the optimum amount.
These stencils are typically 0.008 inches thick and may be
made of brass or stainless steel. For packages such as the
SC−59, SC−70/SOT−323, SOD−123, SOT−23, SOT−143,
SOT−223, SO−8, SO−14, SO−16, and SMB/SMC diode
packages, the stencil opening should be the same as the pad
size or a 1:1 registration. This is not the case with the DPAK
and D
2
PAK packages. If one uses a 1:1 opening to screen
solder onto the drain pad, misalignment and/or
“tombstoning” may occur due to an excess of solder. For
these two packages, the opening in the stencil for the paste
should be approximately 50% of the tab area. The opening
for the leads is still a 1:1 registration. Figure 14 shows a
typical stencil for the DPAK and D
2
PAK packages. The
pattern of the opening in the stencil for the drain pad is not
critical as long as it allows approximately 50% of the pad to
be covered with paste.
Figure 14. Typical Stencil for DPAK and
D
2
PAK Packages
SOLDERING PRECAUTIONS
The melting temperature of solder is higher than the rated
temperature of the device. When the entire device is heated
to a high temperature, failure to complete soldering within
a short time could result in device failure. Therefore, the
following items should always be observed in order to
minimize the thermal stress to which the devices are
subjected.
•
Always preheat the device.
•
The delta temperature between the preheat and
soldering should be 100°C or less.*
•
When preheating and soldering, the temperature of the
leads and the case must not exceed the maximum
temperature ratings as shown on the data sheet. When
using infrared heating with the reflow soldering
method, the difference shall be a maximum of 10°C.
•
The soldering temperature and time shall not exceed
260°C for more than 10 seconds.
•
When shifting from preheating to soldering, the
maximum temperature gradient shall be 5°C or less.
•
After soldering has been completed, the device should
be allowed to cool naturally for at least three minutes.
Gradual cooling should be used as the use of forced
cooling will increase the temperature gradient and
result in latent failure due to mechanical stress.
•
Mechanical stress or shock should not be applied
during cooling.
* * Soldering a device without preheating can cause
excessive thermal shock and stress which can result in
damage to the device.
* * Due to shadowing and the inability to set the wave
height to incorporate other surface mount components, the
D
2
PAK is not recommended for wave soldering.
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SOLDER PASTE
OPENINGS
STENCIL
ONSEMI [ ON SEMICONDUCTOR ]
