Flex PCB Connector: The Complete 101

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Oakley Mae

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A flex PCB connector is an integral part of the electronic device industry.

That’s especially because today, more than ever, there’s an increasing demand for compact and lightweight devices.

In turn, this necessitates the use of more flexible and high-density interconnects.

The ideal connector system for any flexible circuit design depends on factors like retention requirements, the number of interconnects in play, and current carrying needs.

Still, there’s much more on these devices.

This article introduces flexible PCB connectors, including the various style options, types, and features. 

Table of Contents

What Is a Flex PCB Connector?

A connector is what engineers use when a design requires some electrical or mechanical connection, typically a flexible PCB to a rigid PCB.

Other connections where a connector comes in handy include cable harnesses, polyester membrane switches, and flex circuits. 

A connector can have different connection modes, such as polls that insert to vias.

Also, there are several types of connectors. 

Flexible PCB Connector Style Options

Generally, flex PCB connectors fall under the following style options:

ZIF

ZIF connectors require very limited force in the initial stages of insertion.

A latch, lever, or slide normally clamps down on the traces to offer a durable and robust connection.

Also, these connectors allow users to insert a circuit and remove it several times with very little mechanical wear on the traces. 

Low Insertion

Now this connector type utilizes friction to ensure the flex cable retains strength.

With the reduced matting also achieved via the same process, this connector can offer a variety of static application advantages.

In addition, the low insertion force connector is smaller, lighter, and less expensive than its zero insertion force counterpart. 

Insertion

Contrary to the ZIF, you need significant force to insert these connectors.

Unfortunately, this can mar or scratch the conductor’s surface when pulled out.

Nonetheless, they’re affordable and effective when it comes to single-insertion applications.

Crimped Contacts

These are mechanical crimping connectors that pierce through the conductor or dielectric to make a connection. 

FFC (Flat Face Connector) With Shielding

These are connectors specially designed for use in applications like EMI shielding.

Interestingly, they’re pretty much like your standard FPC connector.

Only they have metal shielding that protects that connection from interference. 

Interposer

Interposer connectors are a special subset of the connector sector.

Typically, you apply them in very high counts of 300 and above.

Usually, you’ll clamp it between the rigid PCB and flex circuit using mechanical means.

Then, lock the supporting clamping plate it has. 

The primary role of the clamping plates is the application and distribution of compression forces evenly across the interposer’s surface. 

Male/Female Header

The flex circuit will always have a localized supporting stiffener regardless of the layer count.

Usually, this is FR4, and it supports either the PTH-style or SMT systems. 

In the case of SMt connectors, users link the supporting stiffener to the opposite side of the flex in the connector section.

And to supply it to the parts, it employs a traditional array form for assembly using a standard pick-and-place methodology.

On the other hand, in the case of PTH connectors, you attach the stiffener to the side where the connector gets inserted. 

Board Design

Usually, designers use these connectors to connect two PCBs with FPCs in the middle.

They’re compact and available in several configurations and sizes.

Also, they consist of two connectors, the mating and receptacle connector.

And when it comes to mounting them, you’ll typically mount the mating connector on a single PCB and the latter on a different PCB. 

Insulation Replacement

Usually, these connectors get used in circuits.

That’s because of their reliability and ability to terminate wires without soldering or stripping quickly.

Also, they operate by displacing the insulation on the wire and establishing contact with the conductor beneath them. 

Features of FPC Connectors

Generally, FPC connectors have the following features: 

  • They can accommodate FPC/FFC cables.
FPC/FFC cable connector

(Caption: FPC/FFC cable connector)

  • They’re available in both ZIF and non-ZIF models. 
  • They feature a wide range of centerline spacing options. 
  • They have a short prototype PCB assembly period since all lines get configured. Thus, they eliminate the connection requirements of excess lines. 
  • Because they’re smaller than PCB, they can effectively reduce the volume of the product. That way, they’re much more convenient to carry around.
  • They have kinked legs and solder pads for PCB retention. 
  • They come with a locking feature that provides a high retention force. 

Flex PCB Connector Types

Rigid-Flex PCB Connectors

This is when two or more layers are utilized, with the standard practice being three.

However, depending on the drivers, the number of layers can go as high as ten.

Undoubtedly, the increased layers go hand in hand with a price spike. 

LCD Flex PCB Connectors

Users employ this connector type to connect a flexible circuit to an LCD.

Usually, it carries data signals to and fro, and many also refer to it as a ZIF connector.

In most cases, a flat cable is the kind that’s recommended rather than a round wire.

That’s because it provides better suppression capability of EMI (electromagnetic interference) and RMI.  

Double-Sided Flex PCB Connectors

With this connector, the user utilizes two conductive lakers on two sides, and the appropriate drivers get implemented. 

Mobile Flex PCB Connectors

Now these connectors are inside smart devices and other mobile devices like tablets.

Often, the PCB pitch measures approximately 0.3mm to 0.4mm. 

Charger Flex PCB Connector

This battery FPC connector integrates an FCB as a charging and base material.

Also, it helps break through some of the procedures of conventional lithium batteries. 

Advantages of Flexible PCB Connectors

  • First, folding, bending, or winding these connectors is pretty easy. And what that means is users can arrange them arbitrarily based on their space layout needs. Also, you can expand these connectors or move them in any space. 
  • Secondly, because of their small size, these connectors tend to weigh very little. And by their lightweight feature, they save on space. 
  • Also, they offer good heat dissipation. 
  • In addition, assembling these connectors is very easy. 
  • Further, when it comes to cost, these connectors tend to be very affordable compared to their counterparts. 
  • Moreover, their overall design means they can compensate for the insufficiency associated with flexible substrates.
  • And as far as component carrying capacity goes, this is essential. 

Flex PCB Connector Applications

Usually, you’ll find flex PCB connectors in major compact applications.

For example, in a wide range of medical equipment and portable devices.

Also, these connectors play a crucial role in the automotive industry. 

With high-performance FFC, it’s possible to implement advanced applications in smart automobile lighting.

Also, infotainment and driving assistance systems such as ABS.

Further, engineers use these connectors in navigation safety and support settings. 

FAQs

What Are the Uses of Flex PCB Connectors?

Some examples of how engineers apply the flex PCB connector are in consumer, medical, and automotive electronics devices. 

What Are the Uses of Flex PCBs?

Usually, you’ll find flex PCBs used throughout various industrial sectors to meet high or low-volume flexing requirements. 

What Is the Advantage of Flex PCB?

Flex PCBs have several advantages.

Mainly the fact that with these devices, you don’t have to use bulky wire.

It’s possible to save as much as 60% in space and weight. 

Conclusion

Undoubtedly, PCB connectors are reliable and play a critical role in electronics.

Therefore, you do well to understand how they function so you can take full advantage of them.

Thankfully, you now know the different types, features, and applications.

So you’re in a better position to make a more informed choice of which connector to use on your project.