Authoritative Analysis | Why More and More Core Modules Choose Board-to-Board (B2B) Connections?

In the design of a core module, the connection method is often overlooked, yet it determines the structural stability, signal integrity, and maintainability of the entire system. Over the past few years, a growing number of core modules, development boards, and even the main control systems of entire devices have begun to evolve toward board-to-board connections. Why are more and more manufacturers switching to this solution? Is it really superior? Today, we will thoroughly explain everything from structural design to mass production practice in one go.

In high-compute, high-interface-density SoC systems, board-to-board connectors have become the preferred solution that balances signal integrity with mechanical reliability.

With high-performance SoCs like the RK3588 and RK3576 going mainstream, module-to-carrier signaling is no longer a “few-dozen-line" task—it’s a hundred-plus high-speed channel problem. Board-to-board connectors readily deliver 40–120 pins of high-speed signals while maintaining tight impedance control and excellent signal-integrity (SI) performance.

The LKB3576 carrier board employs four Panasonic AXK5F80537YG board-to-board connectors—80-position, 0.5 mm pitch—secured with four M2 screws.

Compared to FPC or LCC castellated holes, board-to-board connectors deliver:
- Lower signal loss, especially at 2–5 Gbps;
- Stronger EMI shielding through well-grounded pin-to-pin isolation;
- Controllable mating tolerance—precision pin-and-socket alignment within ±0.05 mm.

AI motherboards, industrial gateways, automotive head units, and machine-vision hosts all run multiple simultaneous MIPI, USB 3.0, PCIe, and Gigabit-Ethernet links; board-to-board interconnects preserve the stability and uniformity of these high-speed signals better than any alternative.

In automotive and industrial settings, prolonged vibration and thermal cycling readily loosen interconnects. FPC flex cables in these environments often suffer EMI pickup, signal drift, or intermittent contacts.

Board-to-board connectors, built with metal pins and press-fit sockets, give three mechanical edges:

- High vibration immunity: 60–80 N insertion force survives repeated shock and shake
- Gold-plated contacts: maintain low-resistance paths over thousands of thermal cycles
- Rigid mounting: optional screws and locating posts lock the mated pair to the chassis, eliminating micromotion

For production-line engineers, the biggest draw of board-to-board is solder-free + reusable mating.
- Core modules plug in and pull out in seconds; no reflow required.
- When a board fails, swap the top module—carrier stays in the chassis.
- Cuts SMT cost and lifetime service cost.
- Zero high-temperature cycles, so no heat-stress damage.
- Assembly / disassembly throughput rises 3–5*.
- Larger alignment window allows semi-automatic insertion, forgiving normal handling tolerances.

As embedded devices push toward smaller and thinner form factors, board-to-board connectors enable a vertical stack: two PCBs sit almost face-to-face, maximizing volumetric efficiency.

- Module thickness drops to 2–6 mm
- Shorter internal traces give cleaner signal paths
- A tidier enclosure eases heat-spreading and shielding design

SoC: RK3576, octa-core 64-bit (4*A72 + 4*A53), ARM Mali-G52 MC3 GPU, 6 TOPS NPU
Codec: 4K60 fps H.264/AVC decode, 8K30 fps or 4K120 fps H.265/HEVC decode; 4K60 fps H.264/H.265 encode
Memory: RAM supports LPDDR4/4X/5, ROM supports eMMC 5.1; options 4 GB+32 GB, 8 GB+64 GB, 16 GB+128 GB
OS support: Android, Ubuntu, Buildroot, Debian, openEuler, Kylin
Interconnect: four 80-pin, 0.5 mm pitch, 2 mm height; socket AXK5F80537YG, header AXK6F80347YG, Panasonic board-to-board connector

Board-to-board connection: easy assembly and maintenance, industrial-grade rich interfaces, multi-type expansion support, anti-vibration and anti-interference design, stable long-term operation, suitable for in-vehicle control, AI edge-computing terminals, and industrial smart gateways.

Board-to-board connection is becoming the new standard in embedded hardware design, offering a balanced solution among performance, reliability, and maintainability.