Designed for automated board-assembly equipment, these pick-and-place DIP Sockets on tape-and-reel feature a top pad for vacuum pick-up. The sockets are said to contain "floating" contacts that compensate for the effects of unevenly dispensed solder paste. These contacts allow 0.008" vertical travel, reacting to capillary action as the paste melts. The sockets are supplied on 13.0" diameter reels. They have from eight to 32 pins, with tape widths from 16 to 56 mm. They are protected by a clear, heat-sealed cover tape, which is peeled back when the sockets are presented to the vacuum head. Mill-Max Mfg. Corp., Oyster Bay, N.Y.
Edgeboard Connectors
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E-Snap Edgeboard Connectors are designed for board retention and RF performance without the use of an adhesive. Featuring small protrusions within their slots, they are said to securely "snap" into previously solder-pasted holes as they are slid onto the PCB. They have the ability to lock firmly in place for reflow soldering, while eliminating the time and cost associated with applying an adhesive. They feature 50 W impedance and provide repeatable performance to 18 GHz. Standard subminiature and microminiature interfaces including SMA, SMB and MCX are available. Bomar Interconnect Products Inc., Ledgewood, N.J.
Audio and DC Power Jacks
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These Surface-mount Jacks are said to provide optimum design flexibility. Manufacturers can specify a variety of sizes and options. SMT DC power jacks are available with center pin sizes of 1.0, 1.3, 2.0 and 2.5 mm. SMT audio jacks are available in 4/5/6 conductor, 2.5 and 3.5 mm, mono or stereo. Custom design capabilities are offered. Shogyo International Corp., Plainview, N.Y.
Differential Connectors
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The Micro Giga Connector Series reportedly supports data transfer rates up to 5 Gbps with less than 3 percent forward crosstalk at 100 ps pulse-rise time. They are available in board-to-board, SMT plugs and sockets with a stacking height of 8.0 mm. They have a contact pitch of 0.75 mm, with 0.5 mm pitch between leads. Applications include network switches and hubs, and connections between components in high-speed computer clusters, video systems, test equipment and real-time medical equipment. The products are available with 12, 24 and 36 contact pairs. Fujitsu Takamisawa America Inc., Sunnyvale, Calif.
MTE Headers
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AMPMODU Surface-mount Headers for MTE receptacles are available in right-angle or vertical configurations, and in configurations ranging from two through 25 positions. They reportedly give designers more options to save PCB real estate and streamline assembly. High-temperature materials are said to make the components compatible with infrared and vapor-phase soldering processes. AMP, a part of Tyco Electronics Corp., Harrisburg, Pa.
Audio Jacks
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Surface-mount Audio Jacks are designed for interface with audio equipment including computer speakers, headphones, cell phones and sound cards. They can accept 2.5 and 3.5 mm plugs for either mono or stereo applications. They are manufactured using a polyamide housing, UL-rated 94V-0; 0.012 brass, gold-plated ground terminals; 0.008 phosphor bronze, gold-plated spring contacts; and 0.012 brass, gold-plated shunt terminals. The 2.5 mm jacks are supplied on 22.0 mm-wide tape and the 3.5 mm plugs on 27.0 mm-wide tape; both have a 16.0 mm pitch and come on 14.5" reels. Keystone Electronics Corp., Astoria, N.Y.
Micro-pitch Interfaces
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These SMT, Micro-pitch Interfaces are designed for quiet and high-speed applications, including 0.4 mm pitch with 80 I/Os, 0.5 mm pitch with up to 300 I/Os, 0.635 mmpitch with up to 250 I/Os and 0.8 mm pitch with up to 200 I/Os. The 0.635 mm-pitch version, with a discrete ground plane with through-hole leads on 2.54 mm pitch, can reportedly be used to replace more expensive alternatives without the need for board relayouts. Edgemount, elevated and cable versions of the interfaces are also available. Samtec Inc., New Albany, Ind.
Miniature Connectors
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The SMT Nano Series of 0.025 and 0.0125" centerline connectors conforms to MIL-PRF-83513. The connectors are available in single- and dual-row configurations. An optional metal shell reportedly enhances durability and provides additional mounting schemes. The male contact is stamped from BeCu with a nickel underplate and gold over. The socket contact is a seamless copper, screw-machined item with a similar high-grade finish. Standard and custom applications include MIL/aerospace, medical and telecommunications. Omnetics Connector Corp., Minneapolis, Minn.
CompactFlash Card Connectors
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The MCD-CE Connector System for CompactFlash memory card applications uses 50 contacts on 0.05" (1.27 mm) centers, with the pin contacts on the host side and socket contacts on the card side. Right-angle, host-side connectors in standard and low-profile designs that accept Type I and Type II cards with and without ejectors, as well as socket connectors used on the CompactFlash cards themselves are offered. All styles have insulators molded from high-temperature plastic and SMT-style contacts, and are rated at 125 VAC and 0.5 A per contact. Fujikura America Inc., DDK Connector Div., Santa Clara, Calif.
Multimedia Card Connectors
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Multimedia Card (MMC) Connectors are designed for use in consumer industry and data collection applications. Molded of LCP, these SMT connectors utilize selectively gold-plated phosphor bronze contacts rated for 10,000 mating operations. The connectors are offered in trays or embossed tape for automatic-insertion equipment. The seven-pin connector meets the specifications of the MMC Association. A revised nine-pin SD card design incorporates a write-protect switch, card-lock notch, card-detect and possible ESD grounding mechanism. J.S.T. Corp., Waukegan, Ill.
Parallel Board Connector
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The NeXLev Parallel Board-to-board Connector provides high density of up to 57 real signals per linear centimeter (145 signals per inch). It has a wafer construction organized in 10 rows by up to 30 columns of signal contacts, with each signal wafer having integral stripline shielding. Standard versions contain either 20 or 30 wafers, with each wafer containing 10 real signal contacts. The connector is fully SMT, utilizing ball grid technology for termination to the board. Teradyne Connection Systems, Nashua, N.H.
High-temperature Header
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The high-temperature Through-hole Technology (THT) Header is designed to reduce production time and labor costs associated with conventional wave or flow soldering methods. The heat-resistant plastic housing can withstand temperatures up to 260°C for 10 seconds. Integrated "ribs" located on the bottom are said to prevent solder balls and potential arching. Up to 12 positions in both horizontal and vertical configurations are available. Flanged versions are also available, as well as standard, bulk, reel and tube packaging options. Phoenix Contact Inc., Harrisburg, Pa.
Flexible Jumpers
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Flexible Jumpers are a suitable interconnection for board-to-board, board-to-display, board-to-connector, board-to-sensor or any application requiring flexibility. The jumpers can be customized to fit the I/O space available for SMT applications with Kapton tie bars for alignment to the pads. They can reportedly be manufactured on any pitch down to 0.010", with any material as conductors from 40 to 20 AWG, round, stranded or flat. The dielectric is polyimide H film, making them usable for wave, IR, vapor phase or hot-air soldering. Elmec Mfg., Oceanside, Calif.
Low-profile Connectors
Low-profile Subminiature Surface-mount Connectors are designed for fully automatic SMT handling with tape-and-reel packaging. The black insulator is said to allow swift visual recognition for precise alignment, and the preassembled pick-and-place cover to assure a firm vacuum grip. Other features include a contact lead that reportedly ensures exact placement on the PCB. The low profile makes PCB spacing possible at 8.0 mm. With the connector, PCBs can be placed at distances between 8.0 to 14.0 mm at fixed heights of 12.2, 10.8, 9.4 and 8.0 mm. Erni Components Inc., Chester, Va.
Board-to-board Connectors
The K01 and K02 0.6 mm Series Connectors are for use on fine-pitch, board-to-board applications, with pin counts that range from 20 to 140 contacts. Features include polarized, high-temperature, UL 94V-0-rated thermoplastic housing and gold-over-nickel plating. Stacking heights of 4 to 8 mm are available. Packaging is in tubes or tape-and-reel. USA Speed Tech Inc., Livermore, Calif.
USB Connectors
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These USB Connectors are designed for surface-mount applications, and are available in both Type A and Type B variants. They are said to be compatible with modern surface-mount soldering processes. The Type A jack is a hybrid that features snap-in ground pins for reported better PCB retention before and after soldering. The Type B jack provides notched SMT ground tabs. Kycon Inc., San Jose, Calif.
Miniature Phone Jacks
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The J-2504 family of 2.5 mm Phone Jacks is SMT configuration and either tape-and-reel- or bulk-packaged. The jacks are rated at 10,000 life cycles and feature switched contacts for the tip and ring to allow the application to switch the output from internal to external. The jacks can accept either the 2.5 mm plug that has four positions in a row or the plug that has three contacts on the fourth position that make contact on the outside of the bushing. Connect-Tech Products Inc., Carson City, Nev.
SCSI Connector
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The Ultra SCSI Combo Connector features a three-in-one design that combines data, control and power in one unit. It is available in surface- and straddle-mount. Operating temperature is rated at -40° to 160°C, and insulation resistance is 5,000 MΩ or better at room temperature. Contacts are made of phosphor bronze, copper or brass, and mating contact faces are plated with a gold flash over 50 µin of palladium nickel; solder-connection areas are plated with at least 100 µin of tin-lead solder over nickel. Power contacts are rated at 3 A each and data contacts are rated at 1 A each. Ranoda Electronics Inc., a subsidiary of Ultro Technologies of Singapore, Broomfield, Colo.
Cardbus Eject Header
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The SMT In-Line Cardbus Eject Header on 0.635 mm (0.025") centerline has a simplified single-deck design that is said to be lightweight, low-profile and compact. The header and eject mechanism are separate pieces. The header allows automated SMT soldering. The eject mechanism and header are said to interlock easily without the need for tools. Options include top- and bottom-mount, EMI metal shield covers, stand-offs and push-rod types. FCI USA Inc., Etters, Pa.
High-density Connectors
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ODU-MINIFIX IDCs are mass-terminated to 0.025" center ribbon cable, and are designed to mate with ODU-MINICART SMT headers. They have 0.05" (1.27 mm) X 0.10" (2.54 mm) grid spacing. Headers and sockets are available in several contact counts and board-stacking heights. The alignment pins and vacuum plates reportedly allow the use of automated placement equipment. Typical applications are hand-held medical equipment, bar-code readers, POS devices and scientific instruments. ODU-USA Inc., Camarillo, Calif.
Wire-to-board Connectors
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Series 4573 Wire-to-board Connectors are designed to conserve PCB space and are said to be suitable for a variety of applications, including computer peripherals, printers, security systems and cell phones. Features include phosphor bronze contacts with two to 15 circuits, a large soldering area and contacts that accept 32 to 26 AWG wire. They are made of high-temperature thermoplastic, rated UL 94V-0, to withstand IR or VPR solder methods. Packaging options include tube and tape-and-reel for automated placement. They are available in SMT and through-hole styles. Oupiin America Inc., Santa Clarita, Calif.
Cardedge Connectors
These 0.05" Cardedge Connectors are available in surface-mount styles and with extender card bends. Both versions are available with or without mounting ears, which is said to allow for automated pick-and-place. The parts are available packaged in tubes or on tape-and-reel. The extender card bend parts can reportedly be soldered onto boards as thin as 0.02" or as thick as 0.25". Sullins Electronics Corp., San Marcos, Calif.
SMT Terminal Blocks
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These High-density Surface Mount Terminal Blocks are said to be compatible with any SMT solder process, eliminating the need for secondary solder operations. Standard screw fasteners, with optional through-hole pin mounting, hold the terminal block to the PCB. Wire-to-board connection density is reportedly maximized. They are available in standard 0.150" or 3.5 mm spacing. Options include custom and standard marking, custom colors, selective contact loading and tube packaging. PCD Inc., Peabody, Mass.
Low-profile Connectors
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DA1 Series Low-profile, SMT Interface Connectors are designed for use in compact and slim mobile information terminal devices, such as PDAs, HPCs and notebook PCs. Features include a 3.0 mm (0.010") mating height, reduced mounting space and 0.6 mm (0.024") contact spacing. They have a side locking system and a metal shell for EMI shielding, and are available in 10-, 18- and 26-contact configurations. Board-mounting plugs are available in 10- and 18-contact versions. JAE Electronics Inc., Irvine, Calif.
SmartMedia Connectors
The MCR102 Series of SmartMedia SMT Connectors conforms to the SSFDC Forum proposal for "SmartMedia" miniature storage media. Three types are available: 3.3 and 5.0 V card types and a combined type for both. An incorrect insertion mechanism device reportedly prevents the insertion of the wrong type of voltage card. The low-profile connectors are 40.0 mm long, 38.5 mm wide and 3.0 mm high. The covers are designed to make connection with the ground of the PCB. Insertion and withdrawal life is said to be 10,000 cycles. Hirose Electric (U.S.A.) Inc., Simi Valley, Calif.
TECHNOLOGY UPDATE
By Bob Behrent
Surface-mount technology (SMT) is an idea that is here to stay and evolve. The driving force behind its evolution is market pressure to lower product cost by lowering the cost of manufacturing — the most significant cost determinant following materials. An obvious way to accomplish this is to eliminate steps in the manufacturing process. The steps high on the list to be eliminated, or at least reduced, are those specifically associated with soldering connectors to printed circuit boards (PCBs).
Most passive components are SMT. The time-consuming and costly wave soldering process is necessitated by the remaining minority of through-hole devices. Connectors, mainly those designed for robust applications, are the most prevalent of these devices.
Because there will always be through-hole components, the reflow of through-hole (ROT) method has evolved. This process enables through-hole components to be reflow-soldered alongside SMT components in the reflow oven. By implementing ROT, the durability and reliability of through-hole solder joints are maintained, while the economies of SMT are realized. Many connectors are now provided with PTFE insulators to ensure they can withstand reflow temperature parameters, thus making them "ROT-friendly."
Edgeboard connectors with J-lead/gull-wing leads tend to "float" during reflow, wave or hand soldering. Therefore, a fixturing step (applying an adhesive) is required. Connector manufacturers are proactively addressing this issue by designing through-hole and SMT connectors that lock into PCBs. Engineered specifically to eliminate fixturing, they are slotted to easily snap securely onto or firmly "bite" the board. Moreover, they are configured to support the PCB from both above and below to minimize stress to the solder joint.
Applying additional solder and flux to connector leads is another requisite step, and why the solder-flux bearing lead (SBL) method has evolved. SBL technology mechanically attaches precise and predetermined amounts of solder and flux to leads. All that is required for assembly is to position the connector on the board and process it in the reflow oven. Connector manufacturers are embracing this technology and are producing a wide range of connectors boasting SBL capabilities.
These examples represent only a sampling of the ways in which SMT is evolving to further reduce product cost. However, they demonstrate the industry's responsiveness to the unique challenges posed by connectors.
BOB BEHRENT is president, Bomar Interconnect Products Inc., 1850 Route 46 West, Ledgewood, NJ 07852; (973) 347-4040; Fax: (973) 347-2111; E-mail: bob_behrent@bomarinterconnect.com; Web site: www. bomarinterconnect.com.
