Connectors play a crucial role in the design and manufacture of modern electronic devices. They not only ensure the efficient transmission of signals and power, but also provide a high degree of flexibility and scalability for the system. Among them, the backplane connector has attracted much attention due to its unique performance and application.

1. What is the backplane connector

A backplane connector is a special type of connector used to connect different circuit boards in a computer system or communication device. It is usually mounted on the backplane, which is a printed circuit board (PCB) whose main function is to act as the backbone for signal and power transmission between the various components within the system.

In traditional server, workstation, or mainframe systems, backplane connectors allow motherboards or other circuit boards to communicate with each other through these connection points. These connectors need to be designed to support high-speed data transmission while ensuring signal integrity and electromagnetic compatibility.

2. What are the main functions of the backplane connector

The backplane connector is responsible for transmitting high-speed differential or single-ended signals between the backplane and the board. These signals can include data, addresses, control signals, and other necessary communication signals.

The backplane connector also provides power transmission, ensuring that the board receives adequate power supply. In some cases, backplane connectors must be able to carry large currents.

The backplane connector not only provides electrical connections, but also provides physical support for the board. They are usually designed with positioning devices to ensure that the board can be inserted accurately and locked into place.

Backplane connectors need to be designed to minimize signal reflection, crosstalk, and attenuation to ensure signal integrity. This is achieved through shielding, specific geometries, and other design features.

As system complexity and data transfer rates increase, backplane connectors must be able to provide a large number of connection points in a relatively small space. This requires connectors to be designed with high-density connections in mind.

Backplane connectors need to be designed for easy maintenance and replacement so that they can be repaired quickly in the event of a failure without affecting the operation of the entire system.

Backplane connectors usually follow certain standards, such as DIN 41612 or IEC 60603-2, to ensure compatibility and interchangeability.

For applications that require extremely high data rates, backplane connectors must support high-speed signal transmission, such as 10Gbps, 25Gbps, 56Gbps or higher.

A well-designed backplane connector requires good electromagnetic shielding to reduce the impact of electromagnetic interference (EMI) on the signal.

Backplane connectors allow the system to expand functionality and performance by adding more boards.

Some high-performance backplane connectors also include thermal management features, such as heat sinks or heat pipes, to help reduce the temperature near the connector.

3. What are the common types of backplane connectors

Low speed backplane connector:

Early standards include DIN 41612 and others, and these connectors are mainly used in the telecommunications industry, generally supporting data transfer rates of no more than 1Gb/s. Low-speed backplane connectors are still widely used in some applications that do not require high-speed transmission because of their economy.

Medium speed backplane connector:

When the industry needs speeds in excess of 1Gb/s but is constrained by budget, the medium-speed backplane connector comes into being. The medium-speed backplane connector can usually meet the speed requirements of 4Gb/s to 5Gb/s and is suitable for many modular complex server systems.

High speed backplane connectors:

With the development of technology, there is an increasing demand for higher transmission rates, hence the emergence of high-speed backplane connectors. High-speed backplane connectors can support data transfer rates from 1Gb/s to 112Gb/s and beyond. This type of connector usually uses a thick gold coating to improve reliability, electrical conductivity and electromagnetic shielding.

High-speed backplane connectors may also include specialized designs to improve signal integrity, such as reducing issues such as reflection, crosstalk, and attenuation.

4. Electrical performance specifications of the backplane connector

Signal transmission speed:

Indicates the maximum data transfer rate supported by the connector.

For example, backplane connectors may support data transfer speeds ranging from 1 Gbps to 112 Gbps.

Insertion loss (IL) :

Insertion loss refers to the amount of attenuation of the signal as it passes through the connector.

The lower the insertion loss, the better the signal quality.

It is usually measured in decibels (dB).

Return loss (RL) :

The return loss represents the amount of reflection of the signal in the connector.

Lower return loss means less reflection and better signal integrity.

It is also measured in decibels (dB).

Crosstalk:

Crosstalk refers to the interference between signal lines caused by the interaction of electromagnetic fields.

Crosstalk is divided into near-end crosstalk (NEXT) and far-end crosstalk (FEXT).

The lower the crosstalk, the higher the signal quality.

Common mode rejection ratio (CMRR) :

Represents the connector's ability to suppress common-mode signals.

The higher the common-mode rejection ratio, the stronger the connector's ability to suppress noise.

Common Mode Conversion (CMC) :

Indicates the degree to which the connector converts a difference-mode signal into a common-mode signal.

The lower the CMC, the less interference the differential mode signal is subjected to.

Contact resistance:

Represents the resistance encountered by the signal as it passes through the connector.

The lower the contact resistance, the higher the signal transmission efficiency.

Insulation resistance:

Indicates the resistance of the insulation material inside the connector.

The higher the insulation resistance, the better the insulation performance of the connector.

Voltage resistance (DWV) :

Indicates the maximum voltage that the connector can withstand without breakdown.

The higher the voltage resistance value, the better the safety and reliability of the connector.

Temperature Drift:

Temperature drift refers to the electrical parameter change of the connector at different temperatures.

The smaller the temperature drift, the better the temperature stability of the connector.

Electromagnetic Compatibility (EMC) :

It includes radiative emission (RE) and conducted emission (CE).

These indicators measure the connector's performance in the electromagnetic environment and its sensitivity to external electromagnetic interference.

Ground performance:

Ground performance refers to the efficiency of the ground connection provided by the connector.

Good grounding performance helps reduce interference and improve signal quality.

Power handling capacity:

Indicates the maximum power level that the connector can safely handle.

This is particularly important for applications that need to carry high currents.

Operating frequency range:

Refers to the wide frequency range in which the connector can maintain good performance.

Compatibility:

Some connectors may need to be compatible with other standards or interfaces, such as CPCI, PCI Express, etc.

5. How do I select the right backplane connector?

Determine application requirements:

Specify what type of system the backplane connector will be used in. Consider the overall architecture and topology of the system. Understand the operating environment of the system (e.g. temperature, humidity, vibration, etc.).

Signal type and transmission rate:

Determine the type of signal that needs to be transmitted, including analog signals, digital signals, power signals, and high-frequency signals.

Determine the maximum transmission rate of the signal to select the connector with the appropriate speed class.

If it is a high-speed signal, consider the connector's high-frequency characteristics, such as frequency response, impedance matching, and signal attenuation.

Connector type:

Select the appropriate connector type, such as board-to-board connector, card edge connector, sandwich connector, etc. Consider the mounting method of the connector (such as in-line, surface mount, etc.).

Electrical performance:

Insertion loss (IL), return loss (RL), crosstalk, common mode rejection ratio (CMRR), etc. Consider contact resistance, insulation resistance, withstand voltage and other parameters.

Mechanical properties:

The size and density of the connectors ensure that they match the space requirements of the PCB.

Connector durability and reliability.

Mounting dimensions and positioning of dowel pins to ensure accurate installation.

The voltage loaded on the connector should not exceed 50% of its rated voltage.

Environmental requirements:

Ensure that the connector will function properly in the intended operating environment.

Consider dust, water and impact resistance.

Understand the connector temperature range.

Materials and manufacturing process:

Choose lead-free materials to meet environmental requirements.

Consider the manufacturing process of the connector, such as crimped or welded.

Cost effectiveness:

Balance performance and cost to find cost-effective solutions.

Consider long-term maintenance costs and replaceability of connectors.

Suppliers and Services:

Choose a reputable manufacturer or supplier.

Consider technical support and services from suppliers.

Standards and compatibility:

Ensure connectors comply with relevant industry standards.

Consider the connector's compatibility with existing systems.

Testing and verification:

Before the final selection, the alternative connector may need to be tested to verify that its performance meets the requirements.

Tests can include signal integrity analysis, thermal performance testing, etc.

Sample acquisition and evaluation:

Obtain samples from suppliers and evaluate them.

The final decision is made based on the evaluation results.

6. Well-known brands of backplane connectors

There are many well-known backplane connector suppliers in the market, such as:

7. How to correctly install and maintain the backplane connector?

a. Preparation phase

Carefully read the installation guides and manuals for connectors and related hardware. Learn about special requirements or precautions during installation.

Make sure you have the right tools, such as screwdrivers, wrenches, pliers, magnifying glasses, etc.

For some connectors, specialized tools may also be required, such as crimp tools or specific removal tools.

Clean connectors and PCB boards to ensure there is no dust, grease, or other contaminants.

Clean contact surfaces with a solvent such as anhydrous ethanol or isopropyl alcohol.

Inspect connectors for damage or defects. Make sure all stitches and contact points are in good condition.

b. Installation process

Align the connector with the positioning hole on the PCB board. Use dowel pins or markers to ensure connectors are properly placed.

Gently press the connector into the PCB board or backplane. Make sure the connector goes smoothly into place and does not force the installation.

Hold the connector in place using screws, jigs, or other fasteners. Make sure fasteners are not too tight to avoid damaging connectors or PCB boards.

After the installation is complete, check whether the connector is correctly installed. Verify that all pins and contacts are properly connected and not bent or damaged.

Perform signal integrity and functional tests using appropriate test equipment (such as oscilloscopes, network analyzers, etc.). Verify that all signals are transmitted properly without abnormal insertion loss, return loss, or crosstalk.

For applications that require dust or water resistance, additional sealing measures may be required. Use a sealant or special sealing gasket to protect the connector from environmental factors.

c. Precautions

If it is a high-speed backplane connector, special attention needs to be paid to the length and spacing of the signal line to avoid signal reflection and crosstalk. Special shielding measures may be required to reduce electromagnetic interference.

For connectors carrying large currents, ensure that adequate heat dissipation measures are in place. Check the connector current rating to ensure that it does not exceed the maximum allowable value.

Optical fiber connectors need to be handled with special care to avoid optical fiber damage. Use special tools and cleaners to ensure the cleanliness of the fiber end face.

Take care throughout the installation process to avoid any physical damage to the connector.

Proper testing should be carried out before and after installation to ensure that the connector functions properly.

If you are unsure about the installation process, consult the manufacturer or a professional technician for help.

8. When a fault occurs, how do I diagnose the backplane connector

Preliminary inspection

Check the connector for physical damage, such as bent pins, cracks, or corrosion. Look for visible signs of wear, ablation, or deformation.

Clean the connectors and corresponding slots to remove any dirt or debris that may affect contact. Use compressed air to blow off dust, or use a solvent such as anhydrous ethanol to gently wipe the contact.

Verify that the connectors are properly installed and aligned with the PCB board or backplane. Check that the fixing screws are tight, but do not overtighten them to prevent damage.

Electrical test

Use a multimeter or continuity tester to check the continuity between the connector pins. Make sure that each pin is connected and not disconnected.

Use a multimeter to measure contact resistance. Verify that the contact resistance is within the manufacturer's specified range.

Measure the insulation resistance between the connector pin and the housing using a megasher meter. Make sure the insulation resistance is high enough to prevent short circuits.

Signal integrity test

Use a network analyzer or oscilloscope to measure the insertion loss of the signal. Check whether the signal attenuation is beyond the normal range.

Measure return loss using a network analyzer. Ensure that the return loss is within an acceptable range to reduce reflection.

Test crosstalk between adjacent signal lines using a network analyzer. Verify that the crosstalk level is within acceptable limits to avoid signal interference.

Use a time domain reflectometer (TDR) to check the reflection characteristics of the connector. Analysis of reflection profiles to detect potential problem spots.

Other tests

Thermal imaging inspection: Use an infrared thermal imager to check the connector and its surrounding area for abnormally high temperatures. An abnormal temperature distribution may be an indication of poor contact or overload.

Eye map test: Use an oscilloscope to generate an eye map to visually view signal quality. Make sure that the eye image is clear and that there is no excessive shaking or distortion.

Bit error Rate testing (BER) : Bit error rate testing is performed using a bit error rate tester. Ensure that the bit error rate is within the acceptable range.

troubleshooting

Try replacing the connector or replacing it to another slot. Observe whether the fault persists to confirm whether the problem is related to the connector itself.

If the above steps do not resolve the problem, you can contact the manufacturer's technical support department for help. Provide detailed fault descriptions and technical test results so they can give more professional advice.

Repair and replacement

If the connector is damaged but can be repaired, try servicing it. Note that some types of connectors may not be available for field repair.

If repairs are not feasible or prohibitively expensive, replace the connector with a new one. Make sure the new connector is compatible with the original model and follow the correct installation steps.

With these steps, you should be able to diagnose the problem with the backplane connector and take appropriate steps to repair or replace it. If the problem persists, you may need to further examine other parts of the system or consult a professional.