MMFT3055VL Motorola, MMFT3055VL Datasheet - Page 9

• Manufacturer Part Number: MMFT3055VL
• Description: TMOS POWER FET 1.5 AMPERES 60 VOLT
• Manufacturer: Motorola

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
Motorola TMOS Power MOSFET Transistor Device Data
For any given circuit board, there will be a group of control
150 C
200 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
Figure 16. Typical Solder Heating Profile
100 C
ZONES 2 & 5
DESIRED CURVE FOR LOW
HEATING
“RAMP”
STEP 3
MASS ASSEMBLIES
160 C
ZONES 3 & 6
140 C
HEATING
STEP 4
“SOAK”
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.
SOLDER IS LIQUID FOR
MASS OF ASSEMBLY)
40 TO 80 SECONDS
ZONES 4 & 7
170 C
(DEPENDING ON
HEATING
“SPIKE”
STEP 5
T MAX
STEP 6
VENT
COOLING
PEAK AT
SOLDER
205 TO
STEP 7
JOINT
219 C
MMFT3055VL
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