T3055EL Motorola, T3055EL Datasheet - Page 8

• Manufacturer Part Number: T3055EL
• Description: Search -----> MMFT3055EL
• Manufacturer: Motorola

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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
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.
settings that will give the desired heat pattern. The operator
must set temperatures for several heating zones, and a figure
for belt speed. Taken together, these control settings make up
a heating “profile” for that particular circuit board. On
machines controlled by a computer, the computer remembers
these profiles from one operating session to the next. Figure
18 shows a typical heating profile for use when soldering a
surface mount device to a printed circuit board. This profile will
vary among soldering systems but it is a good starting point.
Factors that can affect the profile include the type of soldering
system in use, density and types of components on the board,
type of solder used, and the type of board or substrate material
being used. This profile shows temperature versus time. The
MMFT3055EL
8
Prior to placing surface mount components onto a printed
The melting temperature of solder is higher than the rated
For any given circuit board, there will be a group of control
Always preheat the device.
The delta temperature between the preheat and soldering
When preheating and soldering, the temperature of the
should be 100 C or less.*
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.
200 C
150 C
100 C
50 C
PREHEAT
ZONE 1
“RAMP”
STEP 1
TIME (3 TO 7 MINUTES TOTAL)
DESIRED CURVE FOR HIGH
MASS ASSEMBLIES
TYPICAL SOLDER HEATING PROFILE
STEP 2
“SOAK”
VENT
150 C
SOLDER STENCIL GUIDELINES
Figure 18. Typical Solder Heating Profile
100 C
SOLDERING PRECAUTIONS
ZONES 2 & 5
HEATING
DESIRED CURVE FOR LOW
“RAMP”
STEP 3
MASS ASSEMBLIES
160 C
ZONES 3 & 6
HEATING
140 C
STEP 4
“SOAK”
stainless steel with a typical thickness of 0.008 inches. The
stencil opening size for the SOT–223 package should be the
same as the pad size on the printed circuit board, i.e., a 1:1
registration.
* Soldering a device without preheating can cause excessive
thermal shock and stress which can result in damage to the
device.
line on the graph shows the actual temperature that might be
experienced on the surface of a test board at or near a central
solder joint. The two profiles are based on a high density and
a low density board. The Vitronics SMD310 convection/in-
frared reflow soldering system was used to generate this
profile. The type of solder used was 62/36/2 Tin Lead Silver
with a melting point between 177 –189 C. When this type of
furnace is used for solder reflow work, the circuit boards and
solder joints tend to heat first. The components on the board
are then heated by conduction. The circuit board, because it
has a large surface area, absorbs the thermal energy more
efficiently, then distributes this energy to the components.
Because of this effect, the main body of a component may be
up to 30 degrees cooler than the adjacent solder joints.
The soldering temperature and time shall not exceed
When shifting from preheating to soldering, the maximum
After soldering has been completed, the device should be
Mechanical stress or shock should not be applied during
Motorola TMOS Power MOSFET Transistor Device Data
260 C for more than 10 seconds.
temperature gradient shall be 5 C or less.
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.
cooling
SOLDER IS LIQUID FOR
MASS OF ASSEMBLY)
40 TO 80 SECONDS
170 C
ZONES 4 & 7
(DEPENDING ON
HEATING
STEP 5
“SPIKE”
T MAX
STEP 6
VENT
COOLING
205 TO 219 C
PEAK AT
SOLDER JOINT
STEP 7