nud3124d ON Semiconductor, nud3124d Datasheet - Page 8

• Manufacturer Part Number: nud3124d
• Description: Automotive Inductive Load Driver
• Manufacturer: ON Semiconductor

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.
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 10 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
The melting temperature of solder is higher than the rated
For any given circuit board, there will be a group of
Always preheat the device.
The delta temperature between the preheat and
soldering should be 100 C or less.*
When preheating and soldering, the temperature of the
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 should be a maximum of 10 C.
200 C
150 C
100 C
50 C
STEP 1
PREHEAT
ZONE 1
RAMP"
TIME (3 TO 7 MINUTES TOTAL)
DESIRED CURVE FOR HIGH
MASS ASSEMBLIES
STEP 2
VENT
SOAK"
150 C
TYPICAL SOLDER HEATING PROFILE
100 C
Figure 10. Typical Solder Heating Profile
SOLDERING PRECAUTIONS
STEP 3
HEATING
ZONES 2 & 5
DESIRED CURVE FOR LOW
MASS ASSEMBLIES
RAMP"
http://onsemi.com
NUD3124D
160 C
STEP 4
HEATING
ZONES 3 & 6
140 C
SOAK"
8
* Soldering a device without preheating can cause excessive
thermal shock and stress which can result in damage to the
device.
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.
The soldering temperature and time should not exceed
260 C for more than 10 seconds.
When shifting from preheating to soldering, the
maximum temperature gradient should be 5 C or less.
After soldering has been completed, the device should
be allowed to cool naturally for at least three minutes.
Gradual cooling should be used since the use of forced
cooling will increase the temperature gradient and will
result in latent failure due to mechanical stress.
Mechanical stress or shock should not be applied
during cooling.
SOLDER IS LIQUID FOR
40 TO 80 SECONDS
(DEPENDING ON
MASS OF ASSEMBLY)
STEP 5
HEATING
ZONES 4 & 7
SPIKE"
170 C
T
MAX
STEP 6
VENT
205 TO 219 C
PEAK AT
SOLDER JOINT
STEP 7
COOLING