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Application: Advantages and Information About ZIF Connectors
There are many types of connectors and termination methods available when designing a flexible circuit. One of the most common is the zero insertion force (ZIF) connector. The reason why the ZIF connector is so popular is that they eliminate the requirement for an added connector. They create a direct connection from the circuit to the mating connector reducing overall weight and cost. Here are a few general facts about ZIF connectors.
1. ZIF Connectors Capabilities and Requirements
- Our equipment allows us to hold ±0.002” tolerance on overall width
- The standard allowable thickness tolerance for 0.012” connectors is ±0.002”
- Specialized material sets have allowed us to hold ±0.001” thickness tolerance on ±0.012” requirement applications verified through multiple capability studies
2. Finishes of ZIF Connectors and Matching With Mating Connector
- Applications that require multiple insertions or greater mechanical force applications (membrane switches) should use hard electrolytic nickel gold (Ni/Au)
- Applications that are static or flex-to-install may only use ENIG/Tin/HASL, depending on the mating connector. It is important to match surface finishes with the contact finishes to inhibit corrosion, especially with tin and gold
- Electroless nickel immersion gold (ENIG) is our most common ZIF plating method and allows for solderability and one surface finish across the entire flex board
3. ZIF Stiffeners
- Polyimide is the most common material added to our standard flex circuit (polyimide) stackup to meet the final ZIF thickness requirement, which is typically 0.012”. Many ZIF connectors have some type of latching mechanism that allows the flex to be inserted and then ultimately clamped down using this latching mechanism
- For ZIF connectors that do not have a latching mechanism, we have utilized an F-R4 (rigid) material as the increased thickness material. The rigid material has the copper etched off which creates a “tooth” for the connector to grab onto versus the polyimide material, which is a smooth material
- ZIF stiffeners are designed to overlap the conductors; 1 mm is the minimum requirement, but 2.5–3 mm is recommended. This provides a “finger hold” for insertion to the connector and prevents mechanical stress and cracking of the conductors. The following images depict the correct design:
Data presented for informational purposes only. Actual values and/or usage is for reference.