Impedance Controlled PCBs
Bittele Electronics provides stack-up and impedance calculations free of charge upon request. Our Field Application Engineers are ready to help you at anytime. We will work with your engineering team at the conceptual level of the PCB design to help you obtain better results in controlling impedance by selecting the proper material and layer stack up.
Bittele's Stack-up Capabilities include:
- Free Stack-up
- Free Impedance
- Hybrid Build
- RF PCB
Bittele Electronics tries to keep common materials in its in-house inventory at all times. The common materials include:
- Higher copper weights: 2 oz, 3 oz; heavier weights (With Lead Time)
- Odd copper weights: H/1 oz, H/2 oz, 1/2 oz
- Foil: 1/4 oz, H oz, 1 oz, 2 oz, 3 oz
Consideration for Selecting Foil-built or Core-built PCBs
By default, Bittele Electronics prefers to use Foil-built PCBs in order make the most economical PCB. When required, we will utilize core-built PCBs as well. Foil-built PCBs not only tend to be more economical than Core-built PCBs, but also they are a bit easier to process. The below picture illustrates the difference between the Foil-built and Core-built PCBs.
Foil-built PCBs utilize 1 less core than the Core-built PCBS in the stack-up. The outside consists of Aluminum Foil. In addition, Foil in different copper weights is much easier to acquire. Since Foil-built PCBs are made of aluminum, they can be used on any builds regardless of what material is being used. The pre-pregs are less costly then cores especially if the core is 5 Mils or thinner.
Core-built PCBs have cores on the outside so there is no need to use Aluminum Foils. Depending upon material availability, at times it may be difficult to acquire the core with uneven copper weights. This forces the PCB manufacturer to etch down the cores, which is costly since labor costs are involved because the PCB manufacturer is actually using higher copper weight material so the process is more costly.
Bittele Electronics uses the industry standard Polar Impedance Calculator SI8000 to calculate impedance. We provide an impedance report and serialized TDR coupons with each shipment free of charge. Typically, designers use published prepreg values from the data sheet to calculate impedance. We have done extensive research over the years to find out our "out or press" prepreg thickness, also known as the squeeze-out thickness. Using these values help us refine our impedance calculations so they are closer to actual values on the finished PCB. This is why we encourage you to work with our team and experienced Field Application Engineers at conceptual level so that we can help you refine your impedance calculations.
We run all manufacturing panels with at least 2 TDR coupon placed diagonally across panel. Both coupons are serialized to panel and array (if present). As mentioned above, we provide serialized TDR coupon & report with all our shipments free of charge.