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 The smaller solder mask keep-out areas are circular, and with pin-compatible Maxi, Mini, Micro Family converters are located on each pad, for the solder joint between the and input / front-end modules. For the first time, circuit- PCB and the SurfMate. The remainder of the pad has a board designers and assemblers have the ability to surface covering of solder mask. The solder paste is dispensed in mount high-density DC-DC converters having current a rectangular area covering the soldering area and part of ratings up to 50 A. (Table 151) the solder mask area. During soldering, the paste will migrate away from the solder mask area to the soldering SurfMate utilizes a pair of surface-mounted headers that area, providing ample volume for quality solder joints. contain sockets to accept the input and output pins of the module. (Table 152) The SurfMate header assembly is Each pad features a non-plated through hole in the center compatible with any thickness PC board, does not of the pad to provide a venting function. It is normal for increase the module mounting height above the board, the solder joint to have a slight void centered on this and is available for all three standard module size: Maxi, through hole. Mini, and Micro (full, half, and quarter bricks). Solder Paste. Solder paste thickness requirements will SurfMates are available packaged in standard recyclable vary depending on whether the board pads are flush or JEDEC-style trays for use with automated pick-and-place elevated from the laminate. equipment and are compatible with standard reflow Elevated Pads (preferred). The ideal height for elevated solder operations. After reflow, the modules are simply pads is 0.0042 ( 0,106 mm) 10%. This can be achieved inserted into the SurfMates. Any secondary soldering by using a 3-ounce copper surface layer. With this height, operation used for through-hole sockets or pins can now a minimum solder paste thickness of 0.006 should be be entirely eliminated reducing manufacturing time and used. Thicker stencils of between 0.008 (0,203 mm) and eliminating dual processes. 0.012 (0,305 mm) are preferred. This unique interconnect scheme combines the inherent Flush-Mounted Pads. For boards with flush-mounted flexibility of component power designs with the manufac- pads a minimum of 0.010 (0,254 mm) solder paste turing efficiency of surface-mount assembly. should be used. Preferred thickness is between 0.012 (0,305 mm) and 0.016 (0,406 mm). PRINTED CIRCUIT BOARD DESIGN AND SOLDER Placement. SurfMate locating pins will engage in the cor- GUIDELINES FOR THE SURFMATE SOCKETING SYSTEM responding PCB holes with a light push of the SurfMate Recommended PCB layout drawings for SurfMates are into the solder paste. The SurfMate should not be taped provided on the Vicor website. All unspecified PCB dimen- or adhered in place. The surface tension of the solder sional tolerances comply with ANSI/IPC-D-300 for Class during reflow will center the SurfMate parts on the PCB, B boards. DXF versions of the PCB outlines are available resulting in accurate positioning. in the Accesorries section of the Vicor website. Equipment and Solder. Soldering of SurfMates should Recommended PCB Construction. The SurfMate system be done using either an infrared or convection oven is capable of very high current-carrying capacity. We reflow process. Solder type Sn63Pb37, or equivalent, with therefore recommend a multilayer PCB with 3-ounce a eutectic temperature of 361F (183C) should be used. copper and internal power and ground planes. Consult Higher temperature solder is not recommended. the drawings for the recommended size and quantity of Standoffs. Mounting standoffs are required for SurfMate via holes for carrying current to the internal planes. applications. The location for standoff holes is shown on Solder Mask and Pad. Two solder mask keep-out areas the PCB layout. A selection chart of recommended are recommended. The larger area encompasses the standoff kits is provided in this section. complete pad area at either end. It ensures the proper Module Pins. SurfMates must be used with modules with height of the 3-ounce solder pads to the surrounding the S or F pin style. laminate. This provides for the optimum gap between the SurfMate and the PCB 0.0042 0.0004 (0,106 mm Module Insertion / Extraction. Sockets and modules are 0,010 mm), minimizing the solder paste thickness rated for up to 5 insertions and extractions before requiring required for quality solder joints. Without this solder mask replacement. When installing a module, lightly place it keep-out area, the gap may widen, (see Flush-Mounted into position so that all pins are properly aligned over each Pads), requiring thicker solder paste to fill the larger gap. 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 Rev 4.9 vicorpower.com Apps. Eng. 800 927.9474 800 735.6200 Page 72 of 88Design Guide & Applications Manual 15. Surface Mount Socketing System (SurfMate) For Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies module removal, Vicor highly recommends the use of our Removing the module at an angle should be avoided as Module Exchange Tool in order to ensure that the sockets this can damage the sockets. are not damaged during the module removal process. SurfMate: Surface Mount Sockets Full Brick (Maxi) Half Brick (Mini) Quarter Brick (Micro) Board Mounting Pin Input Output 5 Sets Input Output 5 Sets Input Output 5 Sets Thickness Style Style Surface All 22100 22101 16017 22100 22102 16021 22103 22104 16025 S, F mount 1. 2. 3. Parameter Specification Value Reference Compatibility F Short RoHS pins Module pin style S Short ModuMate pins Mechanical Contact normal force 100 grams EOL min. GR-1217-CORE, R5-23 (Note4) Exception to GR-1217-CORE Number of mating cycles 5 max. which specifies 25 mating cycle Module engagement force 32 lbs per connector set max. GR-1217-CORE, R5-31,32 Module disengagement force 32 lbs per connector set max. GR-1217-CORE, R5-31,32 Electrical (Note1) Current rating 50 A Maxi , Mini 25 A Micro Gold plating standards, and accepted (Based on 248F (120C) max. socket temp. industry standards such as & 86F (30C) max temperature rise of contact) IICIT, EIA, Bellcore guidelines Low level contact resistance 400 max. GR-1217-CORE, 6.2.1 0.080 (2,03 mm) dia socket (LLCR) Low level contact resistance 300 max. GR-1217-CORE, 6.2.1 0.150 (3,81 mm) dia socket (LLCR) Low level contact resistance 200 max. GR-1217-CORE, 6.2.1 0.180 (4,57 mm) dia sockets (LLCR) Thermal Max continuous use 248F (120C) max. Max socket temperature temperature for gold plating (Note2) GR-1217-CORE Temperature rise 86F (30C) max. (Note3) EIA-364-70A Environmental SurfMate products are tested in random vibration environments to best simulate the broad Shock and vibration 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 151 SurfMate Specifications and Materials (Note1) (Note3) For 80 A operation with Maxi, contact Applications Engineering. ANSI/EIA-364 American National Standards Institute / Electronic Industries Association (Electronic Components, Assemblies & (Note2) GR-1217-CORE issue 1, November 1995 Generic requirements for Materials Association) separable electrical connectors used in telecommunications hardware. A module of NEBSFR, FR-2063 (Note4) The module and socket must be replaced after 5 mating cycles. Maxi, Mini, Micro Design Guide Rev 4.9 vicorpower.com Apps. Eng. 800 927.9474 800 735.6200 Page 73 of 88