DTC114YE
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.
0.5 min. (3x)
TYPICAL
SOLDERING PATTERN
Unit: mm
1.4
SOT–416/SC–90 POWER DISSIPATION
The power dissipation of the SOT–416/SC–90 is a
function of the pad size. This can vary from the minimum
pad size for soldering to the pad size given for maximum
power dissipation. Power dissipation for a surface mount
the equation for an ambient temperature T of 25°C, one can
calculate the power dissipation of the device which in this
case is 125 milliwatts.
A
150°C – 25°C
PD
=
= 125 milliwatts
device is determined by T
, the maximum rated
J(max)
1000°C/W
junction temperature of the die, R , the thermal resistance
θJA
from the device junction to ambient; and the operating
The 1000°C/W assumes the use of the recommended
footprint on a glass epoxy printed circuit board to achieve a
power dissipation of 125 milliwatts. Another alternative
would be to use a ceramic substrate or an aluminum core
board such as Thermal Clad . Using a board material such
as Thermal Clad, a higher power dissipation can be achieved
using the same footprint.
temperature, T . Using the values provided on the data
A
sheet, P can be calculated as follows:
D
T
J(max) – TA
Rθ
PD
=
JA
The values for the equation are found in the maximum
ratings table on the data sheet. Substituting these values into
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.
• The soldering temperature and time should not exceed
260°C for more than 10 seconds.
• When shifting from preheating to soldering, the maximum
temperature gradient should 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.
• Always preheat the device.
• The delta temperature between the preheat and soldering
should be 100°C or less.*
• Mechanical stress or shock should not be applied during
cooling.
• 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 should be a maximum of 10°C.
* Soldering a device without preheating can cause
excessive thermal shock and stress which can result in
damage to the device.
SOLDER STENCIL GUIDELINES
Prior to placing surface mount components onto a printed
circuit board, solder paste must be applied to the pads. A
solder stencil is required to screen the optimum amount of
solder paste onto the footprint. The stencil is made of brass
or stainless steel with a typical thickness of 0.008 inches.
The stencil opening size for the surface mounted package
should be the same as the pad size on the printed circuit
board, i.e., a 1:1 registration.
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