15. Surface Mount Socketing System (SurfMate)
Design Guide & Applications Manual
For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies
SurfMate is a surface-mount connector system for use
with pin-compatible Maxi, Mini, Micro Family converters
and input / front-end modules. For the first time, circuit-
board designers and assemblers have the ability to surface
mount high-density DC-DC converters having current
ratings up to 50 A. (Table 15–1)
SurfMate utilizes a pair of surface-mounted headers that
contain sockets to accept the input and output pins of the
module. (Table 15–2) The SurfMate header assembly is
compatible with any thickness PC board, does not
increase the module mounting height above the board,
and is available for all three standard module size: Maxi,
Mini, and Micro (full, half, and quarter bricks).
SurfMates are available packaged in standard recyclable
JEDEC-style trays for use with automated pick-and-place
equipment and are compatible with standard reflow
solder operations. After reflow, the modules are simply
inserted into the SurfMates. Any secondary soldering
operation used for through-hole sockets or pins can now
be entirely eliminated —reducing manufacturing time and
eliminating dual processes.
This unique interconnect scheme combines the inherent
flexibility of component power designs with the manufac-
turing efficiency of surface-mount assembly.
PRINTED CIRCUIT BOARD DESIGN AND SOLDER
GUIDELINES FOR THE SURFMATE SOCKETING SYSTEM
Recommended PCB layout drawings for SurfMates are
provided on the Vicor website. All unspecified PCB dimen-
sional tolerances comply with ANSI/IPC-D-300 for Class
“B” boards. DXF versions of the PCB outlines are available
in the Accesorries section of the Vicor website.
Recommended PCB Construction.
The SurfMate system
is capable of very high current-carrying capacity. We
therefore recommend a multilayer PCB with 3-ounce
copper and internal power and ground planes. Consult
the drawings for the recommended size and quantity of
via holes for carrying current to the internal planes.
Solder Mask and Pad.
Two solder mask keep-out areas
are recommended. The larger area encompasses the
complete pad area at either end. It ensures the proper
height of the 3-ounce solder pads to the surrounding
laminate. This provides for the optimum gap between the
SurfMate and the PCB 0.0042" ±0.0004" (0,106 mm
±0,010 mm), minimizing the solder paste thickness
required for quality solder joints. Without this solder mask
keep-out area, the gap may widen, (see “Flush-Mounted
Pads”), requiring thicker solder paste to fill the larger gap.
The smaller solder mask keep-out areas are circular, and
are located on each pad, for the solder joint between the
PCB and the SurfMate. The remainder of the pad has a
covering of solder mask. The solder paste is dispensed in
a rectangular area covering the soldering area and part of
the solder mask area. During soldering, the paste will
migrate away from the solder mask area to the soldering
area, providing ample volume for quality solder joints.
Each pad features a non-plated through hole in the center
of the pad to provide a venting function. It is normal for
the solder joint to have a slight void centered on this
through hole.
Solder Paste.
Solder paste thickness requirements will
vary depending on whether the board pads are flush or
elevated from the laminate.
Elevated Pads (preferred).
The ideal height for elevated
pads is 0.0042"( 0,106 mm) ±10%. This can be achieved
by using a 3-ounce copper surface layer. With this height,
a minimum solder paste thickness of 0.006" should be
used. Thicker stencils of between 0.008" (0,203 mm) and
0.012" (0,305 mm) are preferred.
Flush-Mounted Pads.
For boards with flush-mounted
pads a minimum of 0.010" (0,254 mm) solder paste
should be used. Preferred thickness is between 0.012"
(0,305 mm) and 0.016" (0,406 mm).
Placement.
SurfMate locating pins will engage in the cor-
responding PCB holes with a light push of the SurfMate
into the solder paste. The SurfMate should not be taped
or adhered in place. The surface tension of the solder
during reflow will center the SurfMate parts on the PCB,
resulting in accurate positioning.
Equipment and Solder.
Soldering of SurfMates should
be done using either an infrared or convection oven
reflow process. Solder type Sn63Pb37, or equivalent, with
a eutectic temperature of 361°F (183°C) should be used.
Higher temperature solder is
not
recommended.
Standoffs.
Mounting standoffs are required for SurfMate
applications. The location for standoff holes is shown on
the PCB layout. A selection chart of recommended
standoff kits is provided in this section.
Module Pins.
SurfMates must be used with modules with
the “S” or “F” pin style.
Module Insertion / Extraction.
Sockets and modules are
rated for up to 5 insertions and extractions before requiring
replacement. When installing a module, lightly place it
into position so that all pins are properly aligned over each
socket. Then apply even pressure by uniformly tightening
each of the mounting screws through the mounting slots
on the baseplate into the pcb mounted standoffs. For
Maxi, Mini, Micro Design Guide
Page 72 of 88
Rev 4.9
Apps. Eng. 800 927.9474
vicorpower.com
800 735.6200
Design Guide & Applications Manual
For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies
15. Surface Mount Socketing System (SurfMate)
module removal, Vicor highly recommends the use of our
Module Exchange Tool in order to ensure that the sockets
are not damaged during the module removal process.
Removing the module at an angle should be avoided as
this can damage the sockets.
SurfMate: Surface Mount Sockets
Full Brick (Maxi)
Board
Thickness
All
Mounting
Style
Surface
mount
Input
22100
Output
22101
5 Sets
16017
Half Brick (Mini)
Input
22100
Output
22102
5 Sets
16021
Quarter Brick (Micro)
Input
22103
Output
22104
5 Sets
16025
Pin
Style
S, F
1.
2.
3.
Parameter
Compatibility
Module pin style
Mechanical
Contact normal force
Number of mating cycles
Module engagement force
Module disengagement force
Electrical
Current rating
Specification Value
F
S
100 grams EOL min.
5 max.
(Note 4)
Reference
Short RoHS pins
Short ModuMate pins
GR-1217-CORE, R5-23
Exception to GR-1217-CORE
which specifies 25 mating cycle
GR-1217-CORE, R5-31,32
GR-1217-CORE, R5-31,32
Gold plating standards, and accepted
industry standards such as
IICIT, EIA, Bellcore guidelines
GR-1217-CORE, 6.2.1
GR-1217-CORE, 6.2.1
GR-1217-CORE, 6.2.1
Max continuous use
temperature for gold plating
GR-1217-CORE
(Note 2)
EIA-364-70A
(Note 3)
32 lbs per connector set max.
32 lbs per connector set max.
50 A Maxi
(Note 1)
, Mini; 25 A Micro
(Based on 248°F (120°C) max. socket temp.
& 86°F (30°C) max temperature rise of contact)
400 µΩ max.
300 µΩ max.
200 µΩ max.
248°F (120°C) max.
86°F (30°C) max.
Low level contact resistance
0.080" (2,03 mm) dia socket (LLCR)
Low level contact resistance
0.150" (3,81 mm) dia socket (LLCR)
Low level contact resistance
0.180" (4,57 mm) dia sockets (LLCR)
Thermal
Max socket temperature
Temperature rise
Environmental
Shock and vibration
SurfMate products are tested in random vibration environments to best simulate the broad
spectrum of frequencies and amplitudes that may be encountered in typical applications.
Actual system resonant frequencies will depend on PCB construction and mounting details.
For critical, or unusual, shock and vibration environments, the performance of the system
should be independently verified.
Table 15–1
— SurfMate Specifications and Materials
(Note1)
(Note2)
For 80 A operation with Maxi, contact Applications Engineering.
GR-1217-CORE issue 1, November 1995 Generic requirements for
separable electrical connectors used in telecommunications
hardware. A module of NEBSFR, FR-2063
(Note3)
ANSI/EIA-364 American National Standards Institute / Electronic
Industries Association (Electronic Components, Assemblies &
Materials Association)
The module and socket must be replaced after 5 mating cycles.
(Note4)
Maxi, Mini, Micro Design Guide
Page 73 of 88
Rev 4.9
Apps. Eng. 800 927.9474
vicorpower.com
800 735.6200
15. Surface Mount Socketing System (SurfMate)
Design Guide & Applications Manual
For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies
Materials
Headers
Material: Vectra E150i LCP
Flammability
Thermal stability (short term)
Thermal stability (long term)
Solder Cap
Material
Plating
Sockets
Material
Plating
Ratings
Liquid Crystal Polymer
UL94 V-0/5VA
500°F (260°C)
392°F (200°C)
260 cartridge brass (70 Cu, 30 Zn)
100 µ in. min. Cu, followed by 50 to 100 µ in. min. low stress sulfamate-based
electrolytic nickel, followed by 20 µ in. min. soft gold
Brush Wellman Alloy #25 C17200 deep draw quality or equiv. 0.010" thick
Woods nickel strike followed by 50 µ in. min. low stress sulfamate-based electrolytic nickel,
followed by 20 µ in. min. hard gold, followed by 10 µ in. min. soft gold
Table 15–2
— Material properties of SurfMate components
SurfMates
Figure 15–1
— SurfMates; Five pair sets
Figure 15–2
— SurfMates; Individual part numbers
Package
Five pair sets
Individual part numbers
Input
Output
Maxi
16017
22100
22101
Mini
16021
22100
22102
Micro
16025
22103
22104
Notes
Inputs and outputs for five modules
Sold only in multiples of 35 Maxi, Mini, or 40 Micro.
Shipped in JEDEC trays
Table 15–3 —
SurfMates: Part numbering and packaging
Maxi, Mini, Micro Design Guide
Page 74 of 88
Rev 4.9
Apps. Eng. 800 927.9474
vicorpower.com
800 735.6200
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