assembly and soldering information for shd series

ASSEMBLY AND SOLDERING INFORMATION
FOR SHD SERIES SURFACE MOUNT DEVICES
SCOPE:
This document contains recommended procedures and pad sizes for soldering surface mountable SHD1, 1B, SHD-2, 2B, SHD-3, 3A, 3B, SHD-4, 4A, 4B, SHD-5, 5A, 5B, and SHD 6 packages to printed circuit
boards.
MOUNTING:
All of Sensitron’s SHD Series surface mount devices can be attached to common PCB or thermally
enhanced boards using conventional surface mount attachment methods.
Because of the superior power handling capabilities of the SHD Series devices, the user will have to take
care of designing the boards in such a manner to utilize the full capacity of our product. Increased trace
thickness and trace widths for current and thermal conductivity interfaces will have to be considered in
the design of the boards.
ATTACHMENT TO PC BOARDS AND SUBSTRATES:
The circuit designer will have to choose a PCB material that will be rated for the system
temperature-operating envelope. If the system is strictly a commercial product that operates in the -20°C
to +85°C range, the use of the SHD Series with a typical FR4 type board is sufficient. The usage even up
to +115°C have been use successful.
The use of the product in the industrial temperature range of -40°C to +125°C range, then care
should be taken as to choose a board material with a lower coefficient of thermal expansion to increase
long term reliability.
Of course the use of the product where the temperature extremes are –55°C to +150°C
(Aerospace/Military) is what the SHD Series was designed for. In these cases a ceramic insert section
such as DBC Alumina can be used. This is one example and is not intended to exhaust all the possible
attachment materials. Other techniques of controlling the thermal expansion of the board material have
also been utilized over the many years the SHD line has been in production.
CIRCUIT BOARD LAYOUT RECOMMENDATIONS:
The metallized “pad” or “land area” on the end user’s circuitry must be properly designed.
Improper dimensioning or spacing of the land areas may result in poor solder fillets or “tombstoning” The
following drawings illustrate the recommended pad dimensions for the SHD product line. Good land
design will depend on the end user’s application.
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SHD Series
SHD 1
SHD 2
SHD 3
SHD 4
SHD 5
SHD 6
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SHD Series
SHD 3A
SHD 4A
SHD 5A
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SHD Series
SHD 1B
SHD 2B
SHD 3B
SHD 4B
SHD 5B
• 221 West Industry Court Deer Park, NY 11729-4681 (631) 586-7600 FAX (631) 242-9798 •
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SHD AND PCB/SUBSTRATE PREPARATION:
It is recommended that both SHD and substrate be pre-tinned by some means prior to reflow
attachment. Standard SHD devices are pre-tinned as a normal process. Consult factory for other finishes.
REFLOW ATTACHMENT :
Sensitron recommends three methods of reflow attachment: IR, Vapor Phase reflow and Hot air
convection reflow.
Ideal profiles for any of these methods will exhibit a ramp-up of about 2°C/second. The user is
advised never to exceed a rise-rate of 4°C/second. In all three approaches, Sensitron strongly
recommends that the SHD user employ a pre-heat prior to soldering. The user’s board or substrate
should be pre-heated for a minimum of one minute. Careful attention should be paid to ramp down, as
well. After exiting from a soldering operation, boards or substrates should be allowed to cool at their own
natural rate, without heat sinking. The user is advised to cool well below 60°C before attempting any
cleaning operations.
IR REFLOW:
Infrared radiation is a popular method for solder reflow. The IR energy is provided by lamps or
specially muffled panel-type heat sources. Both the board top and bottom sides can be heated,
sometimes with different temperature profiles. Most of the IR furnaces commonly used are of the
unfocused source type with a broadened spectrum of wavelengths. This tends to protect heat sensitive
parts from overheating, yet at the same time improves uniformity of heating. The rate of heating tends to
be a function of the emissivity of the materials and their inherent thermal conductivity. Solder paste
absorbs IR radiation and heat quicker than the SHD. To heat solder paste, it must be exposed to the
radiation on the pads beyond the SHD’s surface. If it is shadowed, the reflow action is not as good. This
means that some attention must be paid to pad dimensions and part placement. Other reflow techniques
using smaller pads may accommodate higher density chip-mounting requirements. A typical IR reflow
profile is shown below:
TYPICAL IR PROFILE
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VAPOR PHASE REFLOW:
Heating is accomplished by the condensation of perfluorinated solvent vapors. Heating rates of all
exposed surfaces is very uniform and repeatable from assembly to assembly.
Higher temperature perfluorinated liquids are also available. The latest vapor phase reflow
equipment are in-line systems, using a conveyer belt. Batch systems are also in use. The immersion time
required for reflow varies from about ten seconds to approximately one minute. The time depends on the
mass of the largest devices to be soldered. Vapor phase soldering has the reputation of being the best
approach for mounting of IC chip carriers on boards using small, high density mounting pads and
interconnections. A typical Vapor Phase reflow profile is shown below
TYPICAL VAPOR PHASE PROFILE
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HOT AIR CONVECTION REFLOW:
This reflow technique is also used to solder SHD devices. A conveyer belt transports the boards
through a tunnel oven with several controlled heating zones. The process is very stable with repeatable
results. Various circuit board materials will behave differently during heating. Materials that withstand the
process without damage such as scorching or lifting must be selected. The time for temperature
excursion above the solder’s melting temperature should be restricted to a maximum of 60 seconds. A
maximum not to exceed temperature of 260°C is recommended. A typical convection reflow profile is
shown below.
TYPICAL HOT AIR CONVECTION REFLOW PROFILE
CLEANING:
Most contaminants generated after soldering operations can be removed by solvent or aqueous cleaning.
Cleaning is most often performed in ultrasonic tanks, vapor degreasers or ultrasonic degreasers. Typical
cleaning cycles may employ more than one step in order to effectively remove both non-polar and polar
contaminants.
• 221 West Industry Court Deer Park, NY 11729-4681 (631) 586-7600 FAX (631) 242-9798 •
• World Wide Web Site - http://www.sensitron.com • E-Mail Address - [email protected] •
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SENSITRON HERMETIC DEVICE STANDARD PACKAGING
¾
¾
¾
¾
¾
¾
Surface Mount Technology
State of the Art Design
Fast Switching – no magnetic elements
Single chip / Multi chip capabilities
Axial, MELF or MOLY Tab
Packaged for easy mounting using vapor solder reflow or a belt furnace
CAPABILITIES:
¾ Voltage: 50V To 1200V (Single Chip)
¾ Voltage: 1500V To 6000V (Multi Chip)
¾ Trr: 25ns To 3000ns
QUALITY:
¾
¾
¾
¾
¾
¾
QPL To JANTX, JANTXV
Screen To JANTX, JANTXV, JANS
ISO 9000 Certified facility
Ultra Fast Diodes With Small Temperature Dependence
Soft Recovery
100% Temperature Cycling
Corporate Headquarters / Factory
Production / R & D Center
221 West Industry Court
Deer Park, NY 11729-4681
Ph: (631) 586-7600
Fax: (631) 586-7652
108 Middlesex Street
North Chelmsford, MA 01863
Ph: 978-251-9911
Fax: (978) 251-4940
To speak with a salesperson, please, contact the factory or your local sales
representative. For information on our other product offering, please visit our
web site at: http://www.sensitron.com. For application/design assistance,
please e-mail us at – [email protected]
• 221 West Industry Court Deer Park, NY 11729-4681 (631) 586-7600 FAX (631) 242-9798 •
• World Wide Web Site - http://www.sensitron.com • E-Mail Address - [email protected] •
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