ntd5n50 ON Semiconductor, ntd5n50 Datasheet - Page 9

• Manufacturer Part Number: ntd5n50
• Description: Power Mosfet 5 Amps, 500 Volts
• Manufacturer: ON Semiconductor

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 17 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.
For any given circuit board, there will be a group of
150°C
100°C
200°C
5°C
PREHEAT
ZONE 1
“RAMP”
STEP 1
TIME (3 TO 7 MINUTES TOTAL)
DESIRED CURVE FOR HIGH
MASS ASSEMBLIES
150°C
STEP 2
“SOAK”
VENT
100°C
TYPICAL SOLDER HEATING PROFILE
Figure 17. Typical Solder Heating Profile
ZONES 2 & 5
DESIRED CURVE FOR LOW
HEATING
“RAMP”
STEP 3
MASS ASSEMBLIES
http://onsemi.com
160°C
ZONES 3 & 6
9
140°C
HEATING
STEP 4
“SOAK”
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 joint.
SOLDER IS LIQUID FOR
MASS OF ASSEMBLY)
40 TO 80 SECONDS
ZONES 4 & 7
(DEPENDING ON
170°C
HEATING
“SPIKE”
STEP 5
T
STEP 6
MAX
VENT
205° TO 219°C
COOLING
PEAK AT
SOLDER
STEP 7
JOINT