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Board to Board Connector
Industrial, IT Datacom
The 0.80 mm pitch floating BTB male plug, vertical SMT, 7.80 mm plastic height, LCP black, is the same housing across three stocked contact counts: 40P (AAC8M040G2078R1), 60P (AAC8M060G2078R1), and 80P (AAC8M080G2078R1). All three run selective 3 µ" gold over 50 µ" nickel on copper-alloy contacts, 80 µ" matte tin on the brass ground plate, ship on tape and reel, and are designed to absorb board-to-board misregistration at mating so a stiff or warped daughter board does not fight the contacts on the way in.
A fixed BTB pair meets at one and only one X/Y position. If the daughter board shifts half a millimetre during assembly, or warps 0.3 mm after reflow, that rigid pair grinds on the way in and grinds on the way out. The float on this plug lets the contact housing move laterally inside the shroud, so a small board-to-board misregistration is absorbed inside the connector instead of being forced into the solder joints or the contact springs.
You give up a little stack-height rigidity, and you buy back mating yield. The premium is worth it on camera and sensor modules, multi-board industrial controls, hinged display links, and any layout where the two mating surfaces come from different SMT lines and cannot be located by a bezel or screw pillar. It is wasted money if your boards can already be located to better than ±0.1 mm — pick a fixed BTB pair instead.
Part number | Contacts | Plastic height | Plating (contact area) | Packing |
|---|---|---|---|---|
AAC8M040G2078R1 | 40 (2 × 20) | 7.80 mm | 3 µ" Au over 50 µ" Ni | Tape & reel |
AAC8M060G2078R1 | 60 (2 × 30) | 7.80 mm | 3 µ" Au over 50 µ" Ni | Tape & reel |
AAC8M080G2078R1 | 80 (2 × 40) | 7.80 mm | 3 µ" Au over 50 µ" Ni | Tape & reel |
The three codes share housing, contact material, plating system, and reel orientation. The only thing that changes is the contact count, and with it the body length, the contact span, and the PCB footprint. The mating height is identical across the three — once the 7.80 mm body is fixed, the board-to-board stack is decided by the socket on the other side, not by the plug.
Body length follows a clean linear rule: A = n × 0.80 + 4.34 mm, where n is the number of contacts per row. That gives 20.34 mm at 40P, 28.34 mm at 60P, and 36.34 mm at 80P. The pin-1-to-last-pin span is (n − 1) × 0.80, so 15.20 / 23.20 / 31.20 mm. The same land pattern is just wider or narrower.
The 7.80 mm body on this plug mates to two socket-body heights, and that is the only thing that decides the final board-to-board stack.
This plug (plastic) | Socket body | Board-to-board stack |
|---|---|---|
7.80 mm | 4.90 mm | 9.00 mm |
7.80 mm | 8.30 mm | 12.75 mm |
If you need 6.50 mm or 8.00 mm, drop down to the 4.80 mm or 6.80 mm plastic body in the same family. If you need 11.75 mm or above, change the socket or move to a different family. The plug alone never sets the stack — it is always the pair.
This is the single most common quoting mistake on 0.80 mm pitch floating BTB. Engineers size the plastic, lock the BOM, and only discover at the mating trial that the matched socket gives a 9.00 mm stack, not the 12 mm they assumed. Quote both halves of the interface before sign-off.
The recommended PCB layout uses the same 0.80 mm pitch as the contact: 0.50 mm wide pads, 6.60 ± 0.20 mm row spacing, a 2.00 ± 0.10 mm ground tab outboard at each end, two Ø0.60 mm alignment posts, and two Ø0.80 mm ground vias. PCB fabrication tolerance is ±0.05 mm. Anything looser and you start seeing paste slumping at the 0.50 mm pad, which on 0.80 mm pitch eats into the solder fillet and drives down yield.
Three assembly notes that matter more than they look:
The shroud around the contact is the alignment feature, not the contact itself. Let the alignment posts do the centring; do not add extra stand-offs at the housing.
The two ground tabs at each end are SMT pads as well as mechanical hold-downs. They are not optional — they carry the moment when the plug is un-mated by hand.
The mating face arrives from the factory with a polyimide cover tape. Leave it on through reflow for vacuum pickup, and remove it before mating. Do not touch the contact area with bare fingers before packing.
Housing is LCP, black, UL94V-0, which is what lets this part sit at 125 °C continuously without softening or blistering. PA9T or nylon alternatives cap out 20 to 30 °C lower and creep on a hot-running board.
The contact is copper alloy. The contact area carries 3 µ" gold over 50 µ" nickel; the solder tail carries gold flash over the same nickel. The nickel is the actual diffusion barrier — the gold on top only needs to be thick enough to stay pore-free through the planned mating cycles. 3 µ" is the practical sweet spot for moderate-cycle work (hundreds of insertions, not thousands). The shell ground plate is brass, 80 µ" matte tin over 50 µ" nickel. The tin solders, the nickel stops the copper in the brass from leaching into the tin over time.
Electrical limits worth designing around: 0.5 A per pin, 50 V, contact resistance 120 mΩ max, insulation resistance 500 MΩ min, operating temperature −40 °C to +125 °C. At 0.5 A through a 120 mΩ pair you are looking at 60 mV of drop and 30 mW of heat per contact — fine for signal and low-current power, marginal for power rails. If you need more than 0.5 A on a single pin, parallel the pins or step up to a heavier family.
Real placements we see on the 7.80 mm / 3 µ" configuration:
Camera and image-sensor modules, where the sensor PCB is small, light, and prone to warp after reflow — the float absorbs the warp at mating instead of forcing it into the contacts.
Stacked board-to-board links in industrial controls, where one board is captive and the other is a field-replaceable module that has to dock by hand.
Display driver boards hinged to a controller board inside a sealed enclosure — the float lets the hinge tolerance ride through mating.
Optical transceivers and small embedded modules where the two mating surfaces come from different SMT lines and a small X/Y offset is unavoidable.
When this is the wrong part: if you need 0.5 A or more on every pin continuously, this is a signal-grade connector and you are pushing it. If your board-to-board stack is outside 9.00 to 12.75 mm with a 7.80 mm body, switch the body height first; do not try to make it work with a non-standard socket. If the two mating boards can be located by mechanical features to better than ±0.1 mm, a fixed BTB pair is cheaper and stiffer.
Every lot ships on tape and reel, with a cover tape across the mating face for vacuum pickup through reflow. The plastic height, plating thickness, and pin count on this page are the stocked configuration. If you need a different plastic height (4.80 or 6.80 mm), a different gold thickness (flash, 1, 5, 10, 15, or 30 µ"), or a pin count outside the 40 / 60 / 80 family, CONSHARE's engineering team can quote on shared tooling. Lead time on stocked pin counts runs two to three weeks from PO; customised configurations typically add one to two weeks depending on what changes. Samples of the three stocked codes are kept on the shelf for engineering builds.
QC on every lot covers plating thickness on the contact area, contact resistance on a pin sample, and a visual on the housing flatness and cover-tape adhesion. The mating side of the connector is not touched by hand before packing.
No. They share the housing cross-section and the same 0.80 mm pitch, but the body length scales with the pin count, so the shroud on a 40-pin will not enclose an 80-pin socket. Match the pin count on both sides of the pair.
The connector is designed for lateral float to absorb board-to-board misregistration at mating. CONSHARE publishes the float envelope with the matched-socket data package; if you need it before the data package is in your inbox, ask the engineering team for the tolerance envelope on this specific code.
The LCP housing and the gold-over-nickel contact system will survive a second lead-free reflow pass for rework. A third pass is where gold porosity and pad wicking start to bite. We recommend one reflow plus one rework cycle.
For sealed assemblies, yes. For anything exposed to condensing humidity or industrial atmospheres, step up to 15 µ" or 30 µ" gold — both are available on the same tooling with a different plating code.
The stocked configuration uses two Ø0.60 mm alignment posts. A boss-style locating feature is available on request; ask the CONSHARE team for the matched drawing before locking the PCB layout.
