What Are Board-to-Board Connectors?
Board-to-board (BTB) connectors electrically and mechanically join two printed circuit boards without a cable between them. They are the backbone of modern stacking architectures – from a compute module that mates to an I/O carrier board, to a sensor daughterboard that sits a few millimeters above a main PCB. TE Connectivity builds one of the broadest portfolios of these interconnects, spanning fine-pitch mezzanine connectors, high-density arrays, and rugged board-to-board systems engineered for industrial and automotive environments.
Because BTB connectors remove cables, they cut assembly steps, improve signal integrity at high speed, and shrink the overall product envelope. The trade-off is that the whole mechanical interface – pitch, stacking height, alignment, and tolerance – has to be engineered deliberately, because there is no cable to absorb misalignment.
Board-to-Board vs Mezzanine vs Wire-to-Board
Terminology gets blurred in day-to-day conversation, so it is worth separating the categories.
Parallel board-to-board
Two boards stack face-to-face or back-to-back and mate through a vertical plug-and-receptacle pair. This is what most engineers picture when they say “mezzanine.”
Mezzanine (stacking) connectors
A subset of parallel BTB designed to hold the boards a defined distance apart – the stacking height. Options range from low-profile 1.5 mm stacks to 20 mm and beyond when tall components need clearance. They appear in modular controllers, single-board computers, and communication modules.
Wire-to-board
Where the connection leaves the board as a cable, you need a wire-to-board system instead. TE, Molex, and JST all build mature wire-to-board families; our guide to wire-to-board connectors compares them directly.
Key Specifications When Choosing a TE Board-to-Board Connector
Pitch
Pitch is the center-to-center spacing of the contacts. Finer pitch (0.4 mm to 0.8 mm) increases density and reduces board area but demands tighter manufacturing tolerances, finer PCB traces, and more careful solder-paste control. Coarser pitch (1.0 mm to 2.54 mm) is more forgiving and easier to rework, which is why it often wins in industrial equipment that must survive field repair.
Stacking height
Decide the distance between the two mating boards early, because it constrains every tall component on both boards. Verify the mounted height – the connector plus the solder joint – rather than the connector body alone.
Mating tolerance and blind mating
When a user cannot see the connector – a cartridge that slides into a housing, for example – you need a connector with guided, blind-mate features and generous float. Check the mating alignment specification: 0.5 mm of permissible misalignment is very different from 2 mm.
Current and voltage rating
BTB connectors are usually rated per contact. Derate the rating for the number of energized contacts, ambient temperature, and altitude. For power delivery between boards, choose families rated for 3 A or more per contact and confirm the temperature rise at your load.
Mating cycles and reliability
Serviceable products need connectors rated for many insertions – 30, 100, or even 500 cycles. If your board is mated once at the factory, a low-cycle connector is the economical choice. Related durability concepts appear in our article on high-reliability terminations.
Popular TE Connectivity Board-to-Board Families
TE groups these products into a few broad families. Fine-pitch mezzanine connectors use 0.4 mm to 1.0 mm pitch for dense, low-profile stacks in portable and embedded systems. High-speed mezzanine connectors add controlled impedance and ground arrangements for differential pairs. Rugged board-to-board systems – some sharing the DNA of TE’s automotive and industrial ranges – add polarization, keying, and higher insertion forces for vibration-prone environments. Two useful references when decoding part numbers are our TE part-number decoding guide and the overview of TE Dynamic series connectors.
Layout and Assembly Best Practices
Give the connector a keep-out zone free of tall components. Add fiducials near the mating pair so automated placement and optical inspection stay accurate. Use the manufacturer’s recommended pad geometry – reducing pad size to gain routing room is one of the most common causes of solder-joint failure. When two boards stack, provide a mechanical standoff or boss so the connector is not the only thing carrying mechanical load; contacts are not structural members.
For high-speed stacks, follow the impedance and pinout guidance in our PCB design guide for high-speed connectors.
Common Failure Modes to Design Out
The three most common BTB failures trace back to design rather than the connector itself. First, solder-joint cracking from differential thermal expansion – mitigate with compliant pad designs and, where the stack is large, a mechanical standoff. Second, contact fretting when micro-motion wears the plating; gold-on-gold interfaces resist this far better than tin. Our contact plating guide explains the trade-offs. Third, partial mating, where one end of a fine-pitch connector seats before the other; use connectors with a defined mating force profile and inspect with X-ray at first article.
Sourcing TE Board-to-Board Connectors Without Supply Risk
Board-to-board connectors are frequently the long-lead item on a new build. Popular fine-pitch families can run 20 to 40 weeks with allocation during demand spikes. Mitigate that by qualifying a second footprint, buying slightly above demand for the first production run, and locking in a distributor relationship that can hold buffer stock.
At By Technology we help design teams and OEMs source TE Connectivity board-to-board and mezzanine connectors with verified traceability, cross-references to alternates, and practical lead-time advice. Tell us your part numbers and target volumes at sales@by-techs.com and we will confirm availability, pricing, and a realistic delivery window.