Choosing the Right Connector Pitch: A Technical Guide to Board-to-Board Design

In the realm of electronic product design, board-to-board connectors play a crucial role in defining the physical architecture, reliability, and performance of multi-PCB systems. Among the many critical parameters that engineers must consider when selecting these components, pitch stands out as perhaps the most fundamental. The connector pitch - the center-to-center distance between adjacent contact pins -has far-reaching implications for product miniaturization, signal integrity, manufacturing yield, and long-term reliability.

Amtek Technology Co., Ltd. offers a comprehensive suite of board-to-board connectors spanning the full spectrum of industry-standard pitches from ultra-fine 0.4mm to robust 1.27mm designs. This article provides a detailed technical analysis of how pitch selection impacts electronic system design and offers guidance ons electing the optimal connector for specific application requirements.

The Technical Significance of Connector Pitch

Before examining specific pitch options, itis important to understand the multidimensional impact of this parameter onelectronic system performance:

 

Board-to-Board Connector Pitch Comparison Actual-scale visualization of Amtek's connector spacing options 0.4mm Pitch (5BB04) Ultra-fine pitch for maximum density applications 0.4mm Key Specifications: • Current: 0.3A • Contacts: 10-100 pins • Density: 625 pins/cm² • Temp: -35°C to +85°C • Voltage: 100V AC • Contact R: 90mΩ Max 0.8mm Pitch (5BB08) Standard pitch balancing density and reliability 0.8mm Key Specifications: • Current: 0.5A • Contacts: 20-200 pins • Density: 156 pins/cm² • Temp: -40°C to +125°C • Voltage: 500V AC • Contact R: 70mΩ Max 1.27mm Pitch (5BB13) Maximum reliability for mission-critical applications 1.27mm Key Specifications (1.27mm Pitch): • Current: 0.5-1.0A • Contacts: 10-100 pins • Density: 62 pins/cm² • Temp: -55°C to +125°C • Voltage: 500V AC • Contact R: 25mΩ Max Actual Size Comparison (1:1 scale illustration) * All connector sizes and pin spacings shown at 10:1 scale for visibility

Figure 1: Visual comparison of different connector pitch options (0.4mm,0.8mm, and 1.27mm) showing the relative size differences and correspondingconnection density capabilities.

Circuit Density and Miniaturization

Pitch directly determines the number of I/Oconnections possible within a given footprint, with smaller pitches enabling higher connection densities. This relationship follows a squared function - halving the pitch potentially allows for four times the connection density within the same board area. For space-constrained applications like smartphones, wearables, and IoT devices, selecting the smallest viable pitch isoften a primary design driver.

Signal Integrity Considerations

As pitch decreases, adjacent conductors move closer together, increasing capacitive coupling and crosstalk potential.This becomes particularly significant in high-speed designs where impedance control and minimal signal distortion are essential. The relationship between pitch and crosstalk can be approximated as:

Crosstalk (dB) ∝ -20log(d/h)

Where d is the pitch distance and his the height from the reference plane.

Mechanical Robustness and Reliability

Finer pitch connectors typically have smaller contact areas and reduced mechanical engagement, potentially impact ingretention force, durability through mating cycles, and resistance to vibration or shock. Applications experiencing mechanical stress may require larger pitch connectors despite the space premium.

Manufacturing Considerations

As pitch decreases, manufacturing tolerances become more critical. For ultra-fine pitch connectors (≤0.5mm),specialized PCB design rules, solder paste printing requirements, and placement equipment become necessary. The yield equation below illustrates how assembly yield decreases exponentially as pitch decreases:

Y = e^(-D×A)

Where Y is yield, D is defect density, and A is the area of solder joint.

Ultra-Fine Pitch: 0.4mm (5BB04 Series)

Amtek's 0.4mm pitch connectors (5BB04series) represent the cutting edge of miniaturization in board-to-board connections, offering exceptional space efficiency for the most compact electronic devices.

Technical Specifications:
  • Current Rating: 0.3 AMP
  • Contact Resistance: 90mΩ Max.
  • Insulation Resistance: 50MΩ Min.
  • Withstand Voltage: 100V AC
  • Operation Temperature: -35°C to +85°C
  • Available Pin Counts: 10, 12, 20, 24, 30, 34, 40, 44, 50, 60, 70, 80, 90, 100
Optimal Applications:
  • Smartphones and mobile devices
  • Wearable technology
  • Ultra-compact IoT devices
  • High-density computing modules
Model Selection Guide:
  • Male standard height (H1=1.15mm): 5BB042C11M-XXG3UH-01
  • Female varying heights:
       
    • H2=1.45mm: 5BB042C14F-XXG3UH-XX
    •  
    • H2=1.95mm: 5BB042C19F-XXG3UH-XX
    •  
    • H2=2.4mm: 5BB042C24F-XXG3UH-XX
    •  
    • H2=2.9mm: 5BB042C29F-XXG3UH-XX
    •  
    • H2=3.4mm: 5BB042C34F-XXG3UH-XX
    •  
    • H2=3.9mm: 5BB042C39F-XXG3UH-XX

Design Considerations: Ultra-fine pitch connectors require rigorous attention to PCBdesign. Land pattern dimensions must be precisely controlled, with recommendedPCB tolerance of ±0.05mm. For optimal reliability, these connectors benefitfrom:

  • Specialized solder paste stencil designs (5mil laser-cut     stainless steel)
  • Enhanced placement accuracy (±0.03mm)
  • X-ray inspection capabilities for production quality control
  • Controlled impedance traces for signal integrity

Fine Pitch: 0.5mm (5BB05 Series)

The 0.5mm pitch connector family (5BB05series) represents an excellent balance between miniaturization andmanufacturability, making it one of the most widely adopted options in modernelectronic design.

Technical Specifications:
  • Current Rating: 0.5A
  • Voltage Rating: 50V AC/DC
  • Contact Resistance: 50mΩ Max.
  • Insulator Resistance: 100MΩ Min.
  • Operating Temperature: -20°C to +105°C
  • Available Pin Counts: 10, 12, 20, 30, 40, 50, 60, 70, 80, 90, 100
Optimal Applications:
  • Consumer electronics
  • Medical devices
  • Industrial controls
  • Telecommunications equipment

Model Selection Guide:

  • Male height options:
       
    • H1=0.8mm: 5BB054C08M-XXG3UR-01
    •  
    • H1=1.0mm: 5BB054C10M-XXG3UR-01
    •  
    • H1=1.5mm: 5BB054C15M-XXG3UR-01
    •  
    • H1=2.0mm: 5BB054C20M-XXG3UR-01
  •  
  • Female height options:
       
    • H2=2.2mm: 5BB054C22F-XXG3UR-01
    •  
    • H2=2.7mm: 5BB054C27F-XXG3UR-01
    •  
    • H2=3.0mm: 5BB054C30F-XXG3UR-01
    •  
    • H2=4.0mm: 5BB054C40F-XXG3UR-01
    •  
    • H2=4.5mm: 5BB054C45F-XXG3UR-01

Design Considerations: The 0.5mm pitch represents a "sweet spot" for manyapplications, balancing miniaturization with more forgiving manufacturing tolerances than 0.4mm designs. Standard SMT processes can typically accommodate this pitch, though care is still needed with:

  • PCB pad design (recommended tolerance of ±0.05mm)
  • Solder paste volume control
  • Thermal profile optimization

Medium Pitch: 0.635mm (5BB06 Series)

Amtek's 0.635mm pitch connector family(5BB06 series) provides enhanced mechanical robustness while maintaining arelatively compact footprint, making it suitable for applications requiring abalance of density and reliability.

Technical Specifications:

  • Current Rating: 0.5A
  • Contact Resistance: See specification tables
  • Insulator Resistance: 1000MΩ Min.
  • Dielectric Voltage: 250V AC for one minute
  • Operating Temperature: -55°C to +85°C
  • Available Pin Counts: 20, 30, 40, 50, 60, 70, 80, 90, 100, 120,  140, 160

Optimal Applications:

  • Industrial equipment
  • Automotive electronics
  • Test and measurement devices
  • Ruggedized consumer products

Model Selection Guide:

  • Male height options:
       
    • H1=5.0mm: 5BB061C50M-XXG0UR-XX
    •  
    • H1=6.0mm: 5BB061C60M-XXG0UR-XX
    •  
    • H1=7.0mm: 5BB061C70M-XXG0UR-XX
    •  
    • H1=8.0mm: 5BB061C80M-XXG0UR-XX
    •  
    • H1=9.0mm: 5BB061C90M-XXG0UR-XX
  •  
  • Female height option:
       
    • H2=4.0mm: 5BB061C40F-XXG0UR-XX

Design Considerations: The 0.635mm pitch offers significantly improved mechanicalstability compared to finer pitches, making it appropriate for applicationssubject to vibration or thermal cycling. Design considerations include:

  • More forgiving PCB tolerance (±0.08mm)
  • Higher retention force (beneficial for devices subject to     handling)
  • Improved current-carrying capacity per pin
  • Enhanced durability through mating cycles

Standard Pitch: 0.8mm (5BB08 Series)

The 0.8mm pitch connector family (5BB08series) is one of Amtek's most versatile connector platforms, offering anexcellent combination of reliability, manufacturability, and reasonabledensity.

Technical Specifications:

  • Current Rating: 0.5 AMP
  • Voltage Rating: 200V AC / 300V DC
  • Insulation Resistance: 100MΩ Min.
  • Contact Resistance: 70mΩ Max.
  • Dielectric Voltage: 500V AC for one minute
  • Operation Temperature: -40°C to +85°C
  • Available Pin Counts: 20, 30, 40, 50, 60, 70, 80, 90, 100, 120,  140

Optimal Applications:

  • Telecommunications infrastructure
  • Industrial automation equipment
  • Medical diagnostic devices
  • Commercial and industrial IoT gateways

Model Selection Guide:

  • Male height options:
       
    • H1=4.75mm: 5BB081C48M-XXG3UR-01
    •  
    • H1=5.75mm: 5BB081C58M-XXG3UR-01
    •  
    • H1=7.75mm: 5BB081C78M-XXG3UR-01
  •  
  • Female height options:
       
    • H2=6.55mm: 5BB081C66F-XXG3UR-01
    •  
    • H2=9.55mm: 5BB081C96F-XXG3UR-01
    •  
    • H2=12.55mm: 5BB081C4AF-XXG3UR-01

Design Considerations: The 0.8mm pitch provides significant design flexibility withrelaxed manufacturing constraints. Key considerations include:

  • Standard SMT equipment compatibility
  • Higher current-carrying capacity per pin
  • Superior mechanical robustness
  • Improved reliability in harsh environments

Robust Pitch: 1.25mm (5BB12 Series)

The 1.25mm pitch connector family (5BB12series) delivers exceptional mechanical stability and electrical performancefor demanding applications where reliability is paramount.

Technical Specifications:

  • Current Rating: 0.5 AMP
  • Insulation Resistance: 100MΩ Min.
  • Contact Resistance: 20mΩ Max.
  • Dielectric Voltage: 500V AC for one minute
  • Operation Temperature: -25°C to +85°C
  • Available Pin Counts: 04, 05, 06, 07, 08, 10, 17, 20

Optimal Applications:

  • Industrial machinery
  • Outdoor and ruggedized equipment
  • High-reliability systems
  • Applications with significant thermal or mechanical stress

Model Selection Guide:

  • Male height options:
       
    • H1=3.95mm: 5BB121C39M-XXG3UR-0X
    •  
    • H1=5.95mm: 5BB121C59M-XXG3UR-0X
  •  
  • Female height option:
       
    • H2=3.4mm: 5BB121C34F-XXG3UR-XX

Design Considerations: The 1.25mm pitch is designed for maximum reliability rather thandensity. Design considerations include:

  • Excellent tolerance for PCB warpage
  • High retention force
  • Superior resistance to vibration and mechanical shock
  • Forgiving manufacturing tolerances
  • Excellent current-carrying capacity

Maximum Reliability: 1.27mm (5BB13Series)

The 1.27mm pitch connector family (5BB13series) represents Amtek's most robust board-to-board connection solution,engineered for mission-critical applications where failure is not an option.

Technical Specifications:
  • Current Rating: 0.5 to 1.0 AMP
  • Insulation Resistance: 10000MΩ Min.
  • Contact Resistance: 25mΩ Max.
  • Dielectric Voltage: 500V AC for one minute
  • Operation Temperature: -55°C to +125°C
  • Available Pin Counts: 10-100
Optimal Applications:
  • Military and aerospace systems
  • Safety-critical industrial controls
  • Automotive powertrain and safety systems
  • Medical life-support equipment
Model Selection Guide:
  • Male height options:
       
    • H1=6.7mm: 5BB13SC67M-XXGXUR-01
    •  
    • H1=8.2mm: 5BB13SC82M-XXGXUR-01
    •  
    • H1=9.9mm: 5BB13SC99M-XXGXUR-01
  •  
  • Female height options:
       
    • H2=6.2mm: 5BB13SC62F-XXGXUR-01
    •  
    • H2=9.0mm: 5BB13SC90F-XXGXUR-01
    •  
    • H2=13.6mm: 5BB13SC6AF-XXGXUR-01

Design Considerations: The 1.27mm pitch is the industry standard for maximum reliabilityapplications, offering:

  • Exceptional tolerance for manufacturing variations
  • Superior mechanical engagement
  • Excellent performance in extreme environments
  • High mating cycle durability
  • Maximum resistance to thermal and mechanical stress
Technical Selection Matrix

To facilitate optimal connector pitch selection, the following matrix provides a quantitative comparison of key parameters across different pitch options:

*Relative scale: * (lowest) to *****(highest)

Application-Specific Selection Guidelines

 

Board-to-Board Connector Pitch Selection Decision Tree Application-based selection guide for optimal connector pitch Start Selection Space Constraints? Primary concern? Extreme Moderate Low Manufacturing Capability? Advanced Standard Environmental Conditions? Harsh Standard Application Reliability Critical? Critical Standard 0.4mm Pitch 5BB04 Series • Ultra-compact • Smartphones • Wearables 0.5mm Pitch 5BB05 Series • Consumer • Medical • Computing 0.635mm Pitch 5BB06 Series • Industrial • Automotive • Ruggedized 0.8mm Pitch 5BB08 Series • Telecom • Industrial IoT • Balanced 1.25mm Pitch 5BB12 Series • Industrial • Outdoor • Reliable 1.27mm Pitch 5BB13 Series • Military • Aerospace • Mission Critical Vibration Concerns? High 0.635/0.8mm For Vibration Low 0.5mm Std Extreme Temperature? Yes 1.27mm -55°C to +125°C

Figure 3: Decision tree for selecting the optimal connector pitch based onapplication requirements, including space constraints, manufacturingcapabilities, environmental conditions, and reliability needs.

Consumer Electronics

For mainstream consumer electronics, the0.5mm pitch (5BB05 series) typically offers the optimal balance betweenminiaturization and manufacturability. For ultra-compact devices likesmartphones and wearables, the 0.4mm pitch (5BB04 series) may be necessarydespite the manufacturing challenges. Key selection factors include:

  • Board space constraints
  • Production volume and manufacturing capabilities
  • Device thickness targets
  • Cost sensitivity
Industrial Equipment

Industrial applications typicallyprioritize reliability over extreme miniaturization, making the 0.8mm (5BB08series) or 1.27mm (5BB13 series) connectors most appropriate. Selection shouldconsider:

  • Vibration and shock requirements
  • Temperature cycling range
  • Expected service lifetime
  • Presence of contaminants or harsh environments
Automotive Electronics

Automotive applications demand exceptional reliability while increasingly requiring higher density connections. The 0.635mm (5BB06 series) and 0.8mm (5BB08 series) pitch connectors often providethe optimal balance, with selection guided by:

  • Temperature extremes (-40°C to +125°C)
  • Vibration profiles (engine-mounted vs. cabin electronics)
  • Service life expectations (10-15 years)
  • Tolerance for humidity and chemical exposure
Medical Devices

Medical device requirements varydramatically based on the specific application. Portable diagnostic equipmentmay benefit from 0.5mm (5BB05 series) connectors for miniaturization, whilelife-supporting equipment typically requires the robustness of 1.27mm (5BB13series) connectors. Key considerations include:

  • Sterilization requirements
  • Reliability requirements (especially for implantable or life-critical devices)
  • Service life expectations
  • Regulatory compliance needs
Conclusion

Connector pitch selection represents afundamental design decision with far-reaching implications for electronicproduct development. By understanding the technical tradeoffs between thevarious pitch options—from the ultra-dense 0.4mm to the highly robust1.27mm—engineers can make informed decisions that optimize their specificapplication requirements.

Amtek Technology's comprehensive range ofboard-to-board connectors (5BB04, 5BB05, 5BB06, 5BB08, 5BB12, and 5BB13 series)provides solutions for virtually any electronic interconnection challenge, fromthe most space-constrained consumer devices to mission-critical systemsdemanding the utmost in reliability.

Link to download Amtet’s product catalog: https://www.amtek-co.com.tw/amtek-ecatalogue/

For application-specific guidance or todiscuss custom connector solutions, our engineering team is available tocollaborate on your next design challenge.

📧 Email:contact@sagacomponents.com
📞 Phone:+46 (0) 8 564 708 00
🌐 Web:https://www.amtek-co.com.tw/search-for-header-socket/