|
Controlled Impedance
PCB Portal has vast experience in advising on the design of controlled impedance technology for a whole range of board types in diverse applications such as Chip Test, Automotive, Medical Aerospace and Military.
We have provided boards featuring, single ended, embedded, surface micro strip, symmetrical strip line, offset strip line, and differential impedance requirements. We often approach separate high-end board manufacturers, who use different impedance calculation and test suites, to compare proposed solutions to the customer’s enquiry. This allows us to advise the “best fit” solution in terms of technical appropriateness, cost, repeatability and reproducibility.
We can run complex calculations on Impedance Calculation and Test suites allowing us to advise on board construction and build, base material selection, dielectric spacing, reference layer position within the construction and design track widths to achieve a customer’s desired result. In many cases the customer details the constraints he is working with and we provide a construction sheet and track width statement to allow him to complete the design.
The same units are used to provide first off, in process, and last off tests on a batch in progress to provide process control over those critical manufacturing stages which directly impact on Impedance characteristics, typically Bonding and Etching processes. In this way we ensure that the process is rigorously controlled to maintain the desired characteristics throughout manufacture.
We use the same test suites to provide final verification that the manufactured board achieves the calculated impedance characteristics. We can supply documented test results for each individual board in the batch, and should the customer desire to carry out their own verification, the accompanying test coupon referenced to the manufacturing panel.
We have provided guidance on some extremely challenging products including:
Flex rigid for Aerospace application, where careful selection of a cross hatching design was required to provide the necessary reference layer, whilst maintaining the required flexibility characteristics.
- Composite material boards where the dielectric properties of conventional FR4 and microwave materials had to be taken into account in the impedance calculation.
- Close tolerance bonding to achieve impedance tolerance of +/-5% (typical offering is +/-10%)
We are confident that whatever a customer’s requirement for impedance control on a board may be, we can offer an effective solution
10/01/2008
 Return to top
|
