Design Guide & Applications Manual 15. Surface-Mount Socketing System (SurfMate) Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies SurfMate is a surface-mount connector system for use with Solder Paste: Solder paste thickness requirements will vary pin-compatible Maxi, Mini, Micro Family converters and depending on whether the board pads are flush or elevated input / front-end modules. For the first time, circuit-board designers from the laminate. and assemblers have the ability to surface mount high-density Elevated Pads (preferred): The ideal height for elevated pads DC-DC converters having current ratings up to 50A. (Table 15.1) is 0.0042in 0,106 mm 10%. This can be achieved by using a SurfMate utilizes a pair of surface-mounted headers that contain three-ounce copper surface layer. With this height, a minimum sockets to accept the input and output pins of the module. solder paste thickness of 0.006in should be used. Thicker stencils of (Table 15.2) The SurfMate header assembly is compatible with any between 0.008in 0,203mm and 0.012in 0,305mm are preferred. thickness PC board, does not increase the module mounting height Flush-Mounted Pads: For boards with flush-mounted pads above the board, and is available for all three standard module size: a minimum of 0.010in 0,254mm solder paste should be Maxi, Mini and Micro (full, half and quarter bricks). used. Preferred thickness is between 0.012in 0,305mm and SurfMates are available packaged in standard recyclable 0.016in 0,406mm . JEDEC-style trays for use with automated pick-and-place equipment Placement: SurfMate locating pins will engage in the and are compatible with standard reflow solder operations. After corresponding PCB holes with a light push of the SurfMate into reflow, the modules are simply inserted into the SurfMates. Any the solder paste. The SurfMate should not be taped or adhered in secondary soldering operation used for through-hole sockets or place. The surface tension of the solder during reflow will center pins can now be entirely eliminated reducing manufacturing time the SurfMate parts on the PCB, resulting in accurate positioning. and eliminating dual processes. Equipment and Solder: Soldering of SurfMates should be This unique interconnect scheme combines the inherent flexibility done using either an infrared or convection oven reflow process. of component power designs with the manufacturing efficiency of Solder type Sn63Pb37, or equivalent, with a eutectic temperature surface-mount assembly. of 361F 183C should be used. Higher temperature solder is not recommended. Printed Circuit Board Design and Solder Guidelines for the SurfMate Socketing System Standoffs: Mounting standoffs are required for SurfMate applications. The location for standoff holes is shown on the PCB Recommended PCB layout drawings for SurfMates are provided layout. A selection chart of recommended standoff kits is provided on the Vicor website. All unspecified PCB dimensional tolerances in this section. comply with ANSI/IPC-D-300 for Class B boards. DXF versions of the PCB outlines are available in the Accesorries section of Module Pins: SurfMates must be used with modules with the S the Vicor website. or F pin style. Recommended PCB Construction: The SurfMate system is Module Insertion / Extraction: Sockets and modules are capable of very high current-carrying capacity. We therefore rated for up to five insertions and extractions before requiring recommend a multilayer PCB with three-ounce copper and replacement. When installing a module, lightly place it into position internal power and ground planes. Consult the drawings for the so that all pins are properly aligned over each socket. Then apply recommended size and quantity of via holes for carrying current to even pressure by uniformly tightening each of the mounting the internal planes. screws through the mounting slots on the baseplate into the pcb mounted standoffs. For module removal, Vicor highly recommends Solder Mask and Pad: Two solder mask keep-out areas are the use of our Module Exchange Tool in order to ensure that the recommended. The larger area encompasses the complete pad sockets are not damaged during the module removal process. area at either end. It ensures the proper height of the three-ounce Removing the module at an angle should be avoided as this can solder pads to the surrounding laminate. This provides for the damage the sockets. 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. Maxi, Mini, Micro Design Guide Rev 5.5 Page 73 of 87 01/2021Design Guide & Applications Manual 15. Surface-Mount Socketing System (SurfMate) Maxi, Mini, Micro Family DC-DC Converters and Configurable Power Supplies SurfMate: Surface-Mount Sockets Full Brick (Maxi) Half Brick (Mini) Quarter Brick (Micro) Board Mounting Five Five Five Pin Input Output Input Output Input Output Thickness Style Sets Sets Sets 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 100g EOL min GR-1217-CORE, R5-23 Exception to GR-1217-CORE d Number of Mating Cycles 5 max which specifies 25 mating cycle Module Engagement Force 32lbs per connector set max GR-1217-CORE, R5-31,32 Module Disengagement Force 32lbs per connector set max GR-1217-CORE, R5-31,32 Electrical a 50A Maxi , Mini 25A Micro Gold plating standards and accepted Current Rating (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 0.080in 2,03mm dia socket (LLCR) Low-Level Contact Resistance 300 max GR-1217-CORE, 6.2.1 0.150in 3,81mm dia socket (LLCR) Low-Level Contact Resistance 200 max GR-1217-CORE, 6.2.1 0.180in 4,57mm dia sockets (LLCR) Thermal Max continuous-use Max Socket Temperature 248F 120C max temperature for gold plating b GR-1217-CORE Temperature Rise 86F 30C max c EIA-364-70A Environmental 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 Shock and Vibration 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. Maxi, Mini, Micro Design Guide Rev 5.5 Page 74 of 87 01/2021