Epec's Blog | Electronics Manufacturing Solutions

In the realm of high-speed electronic design, controlled impedance is an absolute requirement for flex and rigid-flex printed circuit board (PCB) configurations. This blog post delves into the intricacies of achieving controlled impedance in these designs, examining the factors that influence it, the different configurations available, and their impact on PCB thickness and flexibility.

The most important, most critical, and among the most helpful of all documents for building and designing flex and rigid-flex circuits is IPC-6013.

A stiffener is defined as a piece of material adhered to a flexible printed circuit board that rigidizes one zone of the board. While a stiffener holds no electrical value to a PCB, it does maintain a crucial part of most flexible PCBs in the market by hardening that portion of the board.

At first glance, the answer to the question “How many layers can a flexible circuit have before it can no longer bend?” sounds like a simple, black-and-white answer. However, this answer proves to be more complex than expected and involves a great deal of specifications before it can be answered.

One of the key components in the stack-ups for flexible circuits is adhesives. From bonding coverlays to the surface to adhering stiffeners to rigidize the circuit to creating additional use applications for the circuit, adhesives hold many possibilities and can add another dimension of complexity to flexible circuits.

Applications that rely on printed circuit boards (PCBs) to control functions can experience difficulties when having operating components or when designed in slimmed or smaller sizes. Standard rigid circuit boards have to be made in specific sizes and dimensions, which can make it difficult when designing working components that could scrape against and damage the PCB.

Rigid-flex printed circuit boards (PCBs) are a great solution to combine the benefits of both rigid and flex PCBs, but as a result, can accumulate the design challenges of both types alongside creating their own challenges along the way.

Flexible printed circuit boards are a type of printed circuit board (PCB) that has been designed to be more flexible than traditional rigid printed circuit boards. They offer many advantages over their traditional counterparts, including greater design flexibility, improved reliability, and increased cost savings.

Devices are becoming smaller and thinner, requiring circuit boards that can fit into the equipment without adding any additional weight while being flexible enough to route around components. Flexible printed circuit boards offer high-density electrical connections while also reducing space.

Rigid-flex circuit boards are the integration of rigid PCB technology with flexible circuit technology in one unit that is capable of both interconnect and operating functions in a device.