MBRB20100CT
http://onsemi.com
3
INFORMATION FOR USING THE D2PAK SURFACE MOUNT PACKAGE
MINIMUM RECOMMENDED FOOTPRINTS 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 insure proper solder connection
interface between the board and the package. With the
correct pad geometry, the packages will self align when
subjected to a solder reflow process.
mm
inches
0.33
8.38
0.04
1.016
0.67
17.02
0.42
10.66
0.12
3.05
0.24
6.096
D2PAK POWER DISSIPATION
The power dissipation of the D2PAK is a function of the
drain pad size. This can vary from the minimum pad size
for soldering to a pad size given for maximum power
dissipation. Power dissipation for a surface mount device is
determined by TJ(max), the maximum rated junction
temperature of the die, RθJA, the thermal resistance from
the device junction to ambient; and the operating
temperature, TA. Using the values provided on the data
sheet for the D2PAK package, PD can be calculated as
follows:
PD = TJ(max) - TA
RθJA
The values for the equation are found in the maximum
ratings table on the data sheet. Substituting these values
into the equation for an ambient temperature TA of 25°C,
one can calculate the power dissipation of the device which
in this case is 2.5 watts.
PD = 150°C - 25°C= 2.5 watts
50°C/W
The 50°C/W for the D2PAK package assumes the
recommended drain pad area of 158K mil2 on FR-4 glass
epoxy printed circuit board to achieve a power dissipation
of 2.5 watts using the footprint shown. Another alternative
is to use a ceramic substrate or an aluminum core board
such as Thermal Clad. By using an aluminum core board
material such as Thermal Clad, the power dissipation can
be doubled using the same footprint.
GENERAL 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 5 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
D2PAK is not recommended for wave soldering.