Assembly Solder Profile

Assembly Solder Profile
www.vishay.com
Vishay Dale
Assembly Instructions
GENERAL
Vishay offers a wide product selection of inductors and
transformers in a variety of packages. This document
provides instructions on mounting for the different types of
packages, specifically on the different methods of soldering.
If the device is to be mounted near heat-generating
components, consideration must be given to the resultant
increase in ambient temperature.
Influencing parameters on the internal temperature of the
component are as follows:
• Time and power
• Mass of the component
• Size of the component
• Size of the printed circuit board
• Absorption coefficient of the surfaces
• Packing density
SOLDERING INSTRUCTIONS
• Wavelength spectrum of the radiation source
Protection against overheating is essential when a device is
being soldered. Therefore, the connection wires or PCB
traces should be left as long as possible. The maximum
permissible soldering temperature is governed by the
maximum permissible heat that may be applied to the
package.
• Ratio of radiated and convected energy
The maximum soldering iron (or solder bath) temperatures
are given in the individual Datasheets. During soldering, no
forces must be transmitted from the pins to the case (e.g.,
by spreading the pins).
As a general rule of thumb, maximum temperature should
be reached within 360 s and time above solder liquids
temperature should be reached in less than 180 s.
Temperature/time profiles of the entire process and the
influencing parameters are given. The IR reflow profile is
shown in Figure 1.
(c) Wave Soldering
There are several methods for soldering devices onto the
substrate. The following list is not complete.
In wave soldering one or more continuously replenished
waves of molten solder are generated, while the substrates
to be soldered are moved in one direction across the crest
of the wave. Maximum soldering temperature should not
exceed 260 °C for 20 s.
(a) Soldering in the Vapor Phase
(d) Iron Soldering
Soldering in saturated vapor is also known as condensation
soldering. This soldering process is used as a batch system
(dual vapor system) or as a continuous single vapor system.
Both systems may also include a pre-heating of the
assemblies to prevent high temperature shock and other
undesired effects.
This process cannot be carried out in a controlled situation.
It should therefore not be used in applications where
reliability is important. There is no SMD classification for this
process.
SOLDERING METHODS
(b) Infrared Soldering
By using infrared (IR) reflow soldering, the heating is
contact-free and the energy for heating the assembly is
derived from direct infrared radiation and from convection.
The heating rate in an IR furnace depends on the absorption
coefficients of the material surfaces and on the ratio of
component's mass to an As-irradiated surface.
(e) Laser Soldering
This is an excess heating soldering method. The energy
absorbed may heat the device to a much higher temperature
than desired. There is no SMD classification for this process
at the moment.
(f) Resistance Soldering
This is a soldering method which uses temperature
controlled tools (thermodes) for making solder joints. There
is no SMD classification for this process at the moment.
The temperature of parts in an IR furnace, with a mixture of
radiation and convection, cannot be determined in advance.
Temperature measurement may be performed by
measuring the temperature of a certain component while it
is being transported through the furnace.
The temperatures of small components, soldered together
with larger ones, may rise up to 280 °C.
Revision: 13-Jun-12
Document Number: 34213
1
For technical questions, contact: [email protected]
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
Assembly Solder Profile
www.vishay.com
Vishay Dale
TYPICAL REFLOW SOLDERING PROFILE
Peak Reflow Temperature
Duration within 5 °C
of Peak Temp
Temperature
Liquidus Temperature of Solder
Pre-Heat Temp Range
Cool Down Rate
Time Above Liquidus
Ramp Rate
Pre-Heat Dwell Time
Time
Fig. 1 - Infrared reflow soldering (SMD package)
LEAD (Pb)-FREE SOLDER (SnAgCu) REFLOW PROFILE ATTRIBUTES
PROFILE ATTRIBUTE
Peak Reflow Temperature
PROFILE ATTRIBUTE
255 (± 5) °C
Time within 5 °C of Peak Temperature
30 s max.
Liquidus Temperature of Solder
~ 217 °C
Cool Down Rate
6 °C/s max.
Time above Liquidus
60 s to 150 s
Pre-heat Temperature Range
150 °C to 200 °C
Pre-heat Dwell Time
60 s to 120 s
Maximum Ramp Rate
3 °C/s max.
Revision: 13-Jun-12
Document Number: 34213
2
For technical questions, contact: [email protected]
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000
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