PCB Connectors, Board-to-Board: Pitch & Height

A board-to-board (BTB) connector is 2 halves — a plug on the module board and a receptacle on the mainboard — that stack 2 PCBs in parallel (mezzanine) or at right angles. The 3 numbers on every BTB drawing are contact pitch, mated (stack) height and pin count. Every value below comes from the KINGCONN BTB series drawings on this site.

Start with pitch: how dense can your layout go?

Pitch	Typical designs	What it trades
0.4 mm	phones, wearables, camera modules	least board area; tightest alignment, SMT pick-and-place
0.5 mm	module-to-mainboard, IoT boards	density vs yield sweet spot; KINGCONN BTB workhorse
0.8 mm	industrial, networking, in-vehicle infotainment	forgiving alignment, higher current per contact
1.27 mm	power and low-speed signals, serviceability	hand-assembly friendly, often through-hole

Contact pitch is the initial filter in any board-to-board selection. The KINGCONN BTB catalog spans 0.4mm, 0.5mm, 0.8mm and 1.27mm pitches. A 0.4mm-pitch part such as 7BTBF-F0-0208XX suits smartphone-class and module-to-mainboard designs where board area is the constraint; 0.8mm and 1.27mm families trade density for easier assembly and more forgiving alignment in industrial designs. Finer pitch also means tighter coplanarity and solder-paste control on the line — a 0.4 mm part on a hand-assembled board is a yield problem, not a connector problem.

Mated height decides your stack

Stack height	What fits between the boards
0.8 mm	ultra-low profile: boards nearly touching, no parts underneath
5.0 mm	typical module stack: room for SMT passives and low ICs
10.0 mm	spacer class: connectors and inductors fit underneath
15.0 mm	spacer class: heat spreader or shield can between boards

Mated height is the board-to-board distance after mating. The catalog covers profiles from a 0.8mm low-profile stack up to 5.0mm, 10.0mm and 15.0mm spacer-class heights. Pick the height from your mechanical stack — it is the parameter you cannot tune after the enclosure is fixed. Tall stacks add lever arm: for 10.0 mm and above, add board-to-board standoffs so the connector is not the only thing holding the module against vibration.

Pin count follows the interface

KINGCONN BTB series list contact counts from 10 up to 200 positions across the family (for example 10, 12, 14, 16, 18, 20, 22, 24, 26, 30, 34, 36, 40, 44 in the 0.4mm family), so a signal-count change late in the design usually stays inside the same series and footprint family. Count the interface signals plus power and ground pins, then leave spare: high-speed pairs want a ground between them, and power over a fine-pitch BTB is spread across several contacts, not carried on 1.

Plug, receptacle and mating rules

A BTB pair is a plug (header) and a receptacle (socket); the receptacle normally sits on the mainboard and the plug on the module, so the module can be handled without exposing spring contacts. Mating is only guaranteed inside a series at the same pitch and pin count. Polarisation keying, guide posts and metal fittings (hold-downs) are what keep a fine-pitch pair aligned during mating — check that the drawing shows them before choosing the smallest part.

Materials and compliance

Housings are LCP rated UL94V-0; contacts are copper alloy / phosphor bronze. Parts are RoHS compliant, and every specification value published on a part page carries its source drawing number, so your hardware team can verify against the original drawing before layout.

KINGCONN board-to-board connectors

7BTBF-F0-0208XX0.4mm Pitch BOARD TO BOARD MATED HEIGHT 0.80mm HEADER CONNECTOR

7BTBF-F0-0539554XXBTB Female Connector, Side-Entry, Pin Pitch 0.5mm

7BTBF-F0-18XXXXX0.8 PITCH BTB SOCKET

7BTBF-F4-0810B to B Connectors PITCH0.8 10PIN Female

7BTBF-F0-0850XXX0.8 PITCH BTB SOCKET H:5.0 MATING HEIGHT 10.0

7BTBF-F0-0825XXX0.8 PITCH BTB SOCKET H:2.45 MATING HEIGHT 15.0

7BTBF-F0-21127042-XXBoard-to-Board Female Connector, Right-Angle, Pin Pitch 1.27mm

7BTBF-F0-08XXXXX0.8 PITCH BTB SOCKET

0.4, 0.5, 0.8 and 1.27mm pitch board-to-board pairs, from 0.80mm low profile to 15.0mm spacer class.

Shortlist and RFQ

Browse the BOARD TO BOARD series page for the model-level parameter list, or read PCB connector types for how BTB sits next to FPC, card-edge and board-end I/O. Every model card pre-fills an RFQ email — or write to service@kingconn.com.tw with your pitch, height and pin-count targets and our Taoyuan R&D team will respond with drawings and samples.

FAQ

How do I choose the pitch of a board-to-board connector?

Start from board area: 0.4 mm saves the most area but has the tightest alignment tolerance; 0.5 mm balances density and yield; 0.8 mm and 1.27 mm are forgiving to align and carry more current per contact, suited to industrial and power use. The KINGCONN BTB catalog covers 0.4, 0.5, 0.8 and 1.27 mm.

What is stack height?

The board-to-board distance after mating. KINGCONN publishes 0.8, 5.0, 10.0 and 15.0 mm. Once the enclosure and stack are fixed it is the parameter you cannot tune, so fix it before pitch or pin count.

Plug or receptacle: which goes where?

A plug (header) mates a receptacle (socket). The receptacle is usually on the mainboard and the plug on the module. Mating is guaranteed only within a series at the same pitch and pin count; a different series at the same pitch is not automatically compatible.

How do I set the pin count?

Count the interface signals plus power and ground, then leave about 10% spare. KINGCONN BTB families run from 10 to 200 positions, with every step in the 0.4 mm family, so a late signal add usually stays in the same footprint.

Board-to-board or FPC connector?

Boards fixed parallel or at right angles at a fixed distance: board-to-board. Boards that move relative to each other, sit at a variable distance or must pass through the enclosure: a flex cable and an FPC connector.