VICOR Maxi DC Converter User Guide

Maxi DC Converter

Product Information

The Surface-Mount Socketing System (SurfMate) is a connector
system designed for use with pin-compatible Maxi, Mini, and Micro
Family DC-DC Converters and Configurable Power Supplies. It allows
circuit-board designers and assemblers to surface mount
high-density DC-DC converters with current ratings up to 50A.

The SurfMate system consists of a pair of surface-mounted
headers that contain sockets to accept the input and output pins of
the module. It is compatible with any thickness PCB and does not
increase the module mounting height above the board. The SurfMate
system is available for all three standard module sizes: Maxi,
Mini, and Micro (full, half, and quarter bricks).

This unique interconnect scheme combines the flexibility of
component power designs with the manufacturing efficiency of
surface-mount assembly.

Printed Circuit Board Design and Solder Guidelines

Recommended PCB layout drawings for SurfMates are provided on
the Vicor website. All unspecified PCB dimensional tolerances
comply with ANSI/IPC-D-300 for Class B boards. DXF versions of the
PCB outlines are available in the Accessories section of the Vicor
website.

Recommended PCB Construction: The SurfMate system is capable of
very high current-carrying capacity. It is recommended to use a
multilayer PCB with three-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.

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 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.

Flush-Mounted Pads: For boards with flush-mounted pads, a
minimum of 0.010in [0.254mm] solder paste should be used. The
preferred thickness is between 0.012in [0.305mm] and 0.016in
[0.406mm].

Placement: SurfMate locating pins will engage in the
corresponding 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.

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.

15. Surface-Mount Socketing System (SurfMate)

Design Guide & Applications Manual

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 50A. (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 manufacturing 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 dimensional 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 three- 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 three-ounce solder pads to the surrounding laminate. This provides for the optimum gap between the SurfMate and the PCB 0.0042in ±0.0004in [0,106mm ±0,010mm], 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 0.0042in [ 0,106 mm] ±10%. This can be achieved by using a three-ounce copper surface layer. With this height, a minimum solder paste thickness of 0.006in should be used. Thicker stencils of between 0.008in [0,203mm] and 0.012in [0,305mm] are preferred.
Flush-Mounted Pads: For boards with flush-mounted pads a minimum of 0.010in [0,254mm] solder paste should be used. Preferred thickness is between 0.012in [0,305mm] and 0.016in [0,406mm].
Placement: SurfMate locating pins will engage in the corresponding 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 five 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 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.

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15. Surface-Mount Socketing System (SurfMate)

Design Guide & Applications Manual

Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies

Board Thickness
All

Mounting Style
Surface Mount

SurfMate: Surface-Mount Sockets

Full Brick (Maxi)

Half Brick (Mini)

Input Output

Five Sets

Input Output

Five Sets

22100 22101 16017 22100 22102 16021

Quarter Brick (Micro)

Input Output

Five Sets

22103 22104 16025

Pin Style
S, F

Parameter Compatibility
Module Pin Style
Mechanical Contact Normal Force Number of Mating Cycles Module Engagement Force Module Disengagement Force Electrical
Current Rating
Low-Level Contact Resistance 0.080in [2,03mm] dia socket (LLCR) Low-Level Contact Resistance 0.150in [3,81mm] dia socket (LLCR) Low-Level Contact Resistance 0.180in [4,57mm] dia sockets (LLCR) Thermal Max Socket Temperature
Temperature Rise Environmental
Shock and Vibration

Specification Value
F S
100g EOL min 5 max [d] 32lbs per connector set max 32lbs per connector set max
50A Maxi [a], Mini; 25A Micro (Based on 248°F [120°C] max socket temp & 86°F [30°C] max temperature rise of contact)
400 max
300 max
200 max

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

248°F [120°C] max 86°F [30°C] max

Max continuous-use temperature for gold plating
GR-1217-CORE [b] EIA-364-70A [c]

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

[a] For 80A operation with Maxi, contact Applications Engineering. [b] GR-1217-CORE issue 1, November 1995 Generic requirements for separable electrical connectors used in telecommunications hardware.
A module of NEBSFR, FR-2063 [c] ANSI/EIA-364 American National Standards Institute / Electronic Industries Association (Electronic Components, Assemblies & Materials Association) [d] The module and socket must be replaced after five mating cycles.

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15. Surface-Mount Socketing System (SurfMate)

Design Guide & Applications Manual

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)

Ratings
Liquid Crystal Polymer UL94 V-0/5VA 500°F [260°C] 392°F [200°C]

Solder Cap Material
Plating

260 cartridge brass (70Cu, 30Zn)
100in min Cu, followed by 50 ­ 100in min low stress sulfamate-based electrolytic nickel, followed by 20in min soft gold

Sockets Material
Plating

Brush Wellman Alloy #25 C17200 deep draw quality or equiv. 0.010in thick
Woods nickel strike followed by 50in min low stress sulfamate-based electrolytic nickel, followed by 20in min hard gold, followed by 10in min soft gold

Table 15.2 — SurfMate specifications and materials

SurfMates

Figure 15.1 — SurfMates; five-pair sets

Package Five-Pair Sets

Maxi 16017

Mini 16021

Individual Part Numbers Input

22100

22100

Output

22101

22102

Table 15.2 — SurfMate specifications and materials

Figure 15.2 — SurfMates; individual part numbers

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

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15. Surface-Mount Socketing System (SurfMate)

Design Guide & Applications Manual

Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies

Module Exchange Tool

Used in facilitating the proper extraction of modules from InMate or SurfMate sockets. Removal without using the Exchange Tool may cause damage to the sockets.

Description Maxi Exchange Tool Mini Exchange Tool Micro Exchange Tool

Part Number 22827 22828 22829

22827

22829

22828

Standoff Kits for SurfMate Mounted Modules

Figure 15.3 — Slotted baseplate; height above board with standoff

Figure 15.4 — Through-hole or threaded baseplate; height above board with standoff

Heat Sinks

Module Kit #

100 Piece Kit

Slotted Baseplate

Through Hole

20178

20188

Threaded

20179

20189

Through-Hole Baseplate

Through Hole

20176

20186

Threaded

20177

20187

No Heat Sink

20184

20186

Threaded Baseplate

Through Hole

20176

20186

Threaded

N/A

N/A

No Heat Sink

20184

20186

Table 15.4 — Standoff kits for SurfMate mounted modules: part numbering and packaging; module kits contain enough standoffs and screws for one module. 100 piece kits contain standoffs only.

Standoff Kits for SurfMate-Mounted Modules

Board Thickness

Mounting Options

Slotted Baseplate

Through-Hole Baseplate

Nominal [Min / Max] All

Mounting Style
Surface Mount

Through-Hole Heat Sink
Kit-20178
Bag-20188

Threaded Heat Sink
Kit-20179
Bag-20189

Through-Hole Heat Sink
Kit-20176
Bag-20186

Threaded Heat Sink
Kit-20177
Bag-20187

Kits include six (6) standoffs and screws. Mini and Micro modules require a minimum of four (4) standoffs. Bags of one hundred (100) do not include screws; #4-40 thread hardware required.

Threaded Baseplate
Through-Hole Heat Sink
Kit-20176
Bag-20186

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