MURB1660CT Datasheet, PDF (5/6 Pages) Motorola, Inc – ULTRAFAST RECTIFIER 16 AMPERES 600 VOLTS

MURB1660CT
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
7 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/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.
200°C
150°C
100°C
STEP 1
PREHEAT
ZONE 1
“RAMP”
STEP 2
VENT
“SOAK”
STEP 3
HEATING
ZONES 2 & 5
“RAMP”
STEP 4
HEATING
ZONES 3 & 6
“SOAK”
DESIRED CURVE FOR HIGH
MASS ASSEMBLIES
150°C
160°C
STEP 5
HEATING
ZONES 4 & 7
“SPIKE”
170°C
STEP 6 STEP 7
VENT COOLING
205° TO 219°C
PEAK AT
SOLDER JOINT
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 7. Typical Solder Heating Profile for D2PAK
Rectifier Device Data
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