1. Overview
1.1 What is controlled impedance?
1.2 When and why do you need controlled impedance?
1.3 What affects impedance
1.4 Specifying a controlled dielectric board instead of controlled impedance
2. Controlled impedance for manufacturing
2.1 Defining cores and prepregs
2.2 The PCB stack-up design
2.3 Common mistakes to avoid in the stack-up
2.3.1 Prepregs
2.3.2 Impedance trace / space
2.3.3 How to calculate the average effective dielectric constant
2.3.4 High-speed materials
2.4 Why manufacturers change your trace width and spacing
2.5 Stack-up examples for 4, 6 and 8-layer boards
3. How to design a board with controlled impedance
3.1 Determining which signals require controlled impedance
3.2 Annotate the schematic with impedance requirements
3.3 Common mistakes to avoid when designing
3.3.1 Routing differential pairs
3.3.2 Placing components, vias, and coupling capacitors
3.3.3 Length matching
3.3.4 Reference layers for return path of controlled impedance signals
3.4 How to document controlled impedance requirements in the design files
4. Sierra’s capabilities
4.1 How Sierra checks for controlled impedance
4.1.1 Controlled dielectric
4.1.2 Impedance control using TDR coupons
4.1.3 Cross-section
4.2 Sierra’s free Impedance Calculator
5. Sierra Circuits
5.1 About us
5.2 Talk with our experts
