Board-to-Board vs Wire-to-Board Connectors

Two connector families do most of the work inside electronic products: board-to-board (BtB) and wire-to-board (WtB). The names describe the routing — one joins two printed circuit boards directly, the other joins a board to a separate assembly through wires. Choosing between them is mostly a question of geometry, flexibility and vibration.

Board-to-board connectors

A board-to-board connector mates a plug on one PCB with a receptacle on another, with no wires in between. It is used when two boards sit at a fixed, close distance.

• Advantages: compact, low-cost at volume, excellent signal integrity, and a very reliable fixed connection with no loose wires.
• Watch: tolerance stack-up between boards — the connector must absorb alignment and height differences.
• Common options: fine-pitch (0.4–1.0 mm) for compact electronics, and larger 1.27–2.54 mm pitches for power and industrial use.

Wire-to-board connectors

A wire-to-board connector has a header on the PCB and a mating housing crimped to wires that run to another module — a display, sensor, motor, battery or keypad.

• Advantages: flexibility — the two ends can be any distance apart, routed around other parts, and disconnected for service.
• Watch: choose a locking or polarized housing so it cannot plug in backwards or shake loose in high-vibration products.
• Common options: wafer/terminal-style connectors and crimped housings from roughly 1.0 mm to 6.2 mm pitch, with current rating rising as pitch increases.

How to choose

Factor	Board-to-board	Wire-to-board
Board positions	Fixed, close together	Separate / moving / distant
Space	Very compact (fine pitch)	Needs room for wires
Flexibility / service	Fixed, not removable	Detachable, routable
Vibration	Rigid — can transfer stress	Wires absorb movement
Signal integrity	Excellent	Good (keep runs short)
Key specs	Pitch, stacking height, depth	Pitch, current, locking style

Pitch and current

For both families, pitch is the starting point and broadly tracks current: fine-pitch (0.4–0.8 mm) handles low-voltage signals in phones and wearables; 1.25–2.5 mm handles most board and power signals; 3.0 mm and above is used for higher-current power. Always confirm the published current rating rather than assuming it from pitch.

Rule of thumb: if the boards are fixed and close, board-to-board is the most compact and reliable. If anything is separate, moving, removable or subject to vibration, use wire-to-board.

Related products

• Wafer Series
• Pin Header Series
• FPC Series