Home [Press Release] Hirose Electric Develops the World's Smallest Class Floating Board-to-Board Connector, the BM54 Series with 3.8mm Width.

Hirose Electric Develops the World's Smallest Class Floating Board-to-Board Connector, the BM54 Series with 3.8mm Width.
November 7, 2023

Hirose Electric Develops the World's Smallest Class*1 Floating Board-to-Board Connector, the BM54 Series with 3.8mm Width.
125°C heat resistance and high contact reliability with two-point contacts for automotive specifications

*1 In board-to-board connectors with ±0.4mm floating range

Hirose Electric has developed the BM54 series of board-to-board floating connectors. The width dimension of 3.8mm is the world’s smallest class for board-to-board connectors with a wide floating amount of ±0.4mm.

BM54 Series

● Connection Reliability and Assembly Efficiency Inside Automotive Devices are Required with the Spread of Autonomous Driving

The number of in-vehicle cameras and LiDARs is increasing due to the mandatory installation of rear cameras and the evolution of autonomous driving. When using non-floating connectors to connect these devices internally, there are cases where multiple connectors cannot be placed on a single board because misalignment between boards cannot be absorbed, and high-precision work such as optical axis adjustment is difficult when assembling cameras and high-performance LiDAR. In addition, sensing devices placed on the periphery of automobiles affect the vehicle design, so miniaturization is also a key issue. To address these issues, there is a need for board-to-board connectors that are compact and have a floating function to absorb misalignment between boards.

● Automotive Quality Connector with ±0.4mm Large Floating Amount and Small Size

In response to this need, Hirose has developed the "BM54" series, which absorbs board misalignment with a large floating amount of ±0.4mm in the XY direction, thereby improving contact reliability and contributing to more efficient application assembly. The width of this series is 3.8mm, which is the world's smallest class board-to-board connectors with a floating function, contributing to the miniaturization of applications. The two-point contact design and large effective mating length of ±0.4mm*2 provide high contact reliability and heat resistance up to 125°C, making it suitable for use in automotive environments.

*2 In case of 3.5, 4.0 and 4.5mm

Large Floating Range ±0.4mm in X and Y Directions (Mated, 30pos.)

BM54 Series

Features: Small Floating Board-to-Board Connector, 125℃ Heat Resistance, “BM54” Series for Automotive Applications
1.0.4mm pitch, 3.8mm width, world’s smallest class in Floating board-to-board connectors
2.Absorption of misalignment
  X and Y directions : Floating range ±0.4mm
  Z direction : Effective mating length ±0.3mm (Stacking height = 3.0mm)
                   ±0.4mm (Stacking height = 3.5 to 4.5mm)

3.125℃ heat resistance for automotive specifications
4.High contact reliability with two-point contact
5.Supports PCI-ex Gen4 (16Gbps) and MIPI D-PHY Ver.2.1

● Future Product Development

The newly developed "BM54" series will be expanded with the following stacking heights and pin count variations in the future
- Under mass production
 Stacking height : 3.0mm No. of pos. : 30
- Under development planning
 Stacking height : 3.0, 3.5, 4.0, 4.5mm No. of pos. : 10, 20, 30, 40
We aim to further expand the market not only for in-vehicle equipment but also for consumer and industrial equipment as ultra-compact floating connectors that connect rigid circuit boards.

● Corporate Profile, Related Information