Fine Pitch FPC Basics

Fine Pitch FPC

Fine pitch flexible printed circuit (FPC) connectors are a great option for situations where small centerline spacing makes large wire-to-board interconnects impractical.

Our fine pitch FPC solutions are reliable interconnects that use an actuator to secure the cable termination so no tooling is required. Consider the following advantages and aspects of FPC connectors when designing for smaller centerline, lower profile heights, and lighter interconnect solutions.

FPC Basics Figure A
Figure A
FPC Basics Figure B
Figure B

All of our fine pitch FPC products feature a staggered tail orientation. This orientation type means that the layout of the front and rear contacts are staggered as illustrated in Figure A.

 

When the tail orientation is staggered, it is important to remember that you can measure the centerline by measuring the distance between the center of the front contact and the center of the rear contact as illustrated in Figure B.

FPC Basics Figure C
Figure C

Centerline can be measured many different ways, however, in general it is simply the spacing between the center of one contact and the center of the contact next to it.


You can note the centerline of our fine pitch FPC product by looking at the contacts of the connector itself, shown in Figure C, or by the method already described in Figure B.

All of our fine pitch FPC connectors incorporate a flip lock actuator for greater printed circuit retention. This termination method also allows for zero insertion force, which is why this product is commonly referred to as a ZIF connector. The operation of a flip lock actuator can be seen in the images below.

Front Flip Lock Actuator

   

Front Flip Lock Actuator Step 1
Step One: Open the flip lock actuator. The actuator hinges open towards the back side of the connector (away from the FPC).
Front Flip Lock Actuator Step 2
Step Two: Insert the FPC into the connector.
Front Flip Lock Actuator Step 3
Step Three: Close the flip lock actuator. The actuator hinges close towards the front side of the connector (towards the FPC).
Front Flip Lock Actuator Step 4
Step Four: Your FPC is now securely mated with the connector.

Back Flip Lock Actuator

   

Back Flip Lock Actuator - Step 1
Step One: Open the flip lock actuator. The actuator hinges open towards the front side of the connector (towards the FPC).
Back Flip Lock Actuator - Step 2
Step Two: Insert the FPC into the connector.
Back Flip Lock Actuator - Step 3
Step Three: Close the flip lock actuator. The actuator hinges closed towards the back side of the connector (away from the FPC) and closes with a tactile click.
Back Flip Lock Actuator - Step 4
Step Four: Your FPC is now securely mated with the connector.
TE Connectivity (TE)

Many of our fine pitch FPC products are available in both upper (top) or lower (bottom) contact versions. This attribute represents which portion of the contact the FPC interacts with. As you can see from the image below, the FPC contacts are formed in a “U” shape. Only one prong of that U-shaped contact interfaces with the FPC contacts. Choosing the correct contact design is generally based on the orientation of the flexible printed circuit, as described below. 

FPC Upper vs Lower Contacts

If the contacts of the FPC are facing up (away from the board), the upper contact version (left) is required. If the contacts of the FPC are facing down (towards the board), the lower contact version (right) is required.

What’s the advantage of angled insertion?

   

FPC Straight insertion
Straight Insertion: Typically FPCs are inserted straight into the interconnect (or parallel to the PCB). This insertion method uses valuable real estate in front of the interconnect, which can be a problem as today’s devices are trending towards miniaturization.
FPC Angled insertion:
Angled Insertion: With the angled or slanted insertion you can see how the FPC enters the interconnect from an angle. This insertion method frees up the space in front of the interconnect that would not have been available using the standard insertion method.
FPC Advantage of angled insertion
Advantage of Angled Insertion: In this image, you can see how the saved board space can be optimized when using the angled insertion interconnect. You can easily use the freed board space to run a group of FPC connectors or to place anything in this space on the PCB.