MBRB1545CT(2000) Ver la hoja de datos (PDF) - ON Semiconductor
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MBRB1545CT Datasheet PDF : 8 Pages
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MBRB1545CT
RECOMMENDED PROFILE FOR REFLOW SOLDERING
For any given circuit board, there will be a group of
control 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 5 shows a typical heating profile
for use when soldering the D2PAK 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 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/infrared 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.
200°C
STEP 1 STEP 2 STEP 3
STEP 4
STEP 5 STEP 6 STEP 7
PREHEAT VENT HEATING
HEATING HEATING VENT COOLING
ZONE 1
RAMP"
SOAK" ZONES 2 & 5 ZONES 3 & 6 ZONES 4 & 7
RAMP"
SOAK"
SPIKE"
205° TO
219°C
DESIRED CURVE FOR HIGH
170°C
PEAK AT
MASS ASSEMBLIES
160°C
SOLDER
150°C
JOINT
150°C
100°C
100°C
140°C
SOLDER IS LIQUID FOR
40 TO 80 SECONDS
(DEPENDING ON
MASS OF ASSEMBLY)
DESIRED CURVE FOR LOW
MASS ASSEMBLIES
50°C
TIME (3 TO 7 MINUTES TOTAL)
TMAX
Figure 5. Typical Solder Heating Profile
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