PCB line impedance calculator
Here's a PCB-trace impedance calculator (150KB). This software takes the physical dimensions of the traces, as well as the characteristics of the dielectric (board) and the position of the layers, to calculate both single line and differential impedance, in microstrip and stripline modes.
LVDS
I originally developed this calculator to build an LVDS board.
LVDS is a way to transfer large amount of data between chips, while keeping power consumption and wire count low. LVDS uses a differential mode of transmission, so every channel uses a pair of lines. Because each LVDS pair can reach speeds up to 1Gbps, their line termination is of critical importance.
Each pair of lines needs to be terminated by a resistor set across the pair. The value of this resistor must be equal to the pair differential impedance.
LVDS related links
- UltraCAD Calculators
- LVDS design notes (TI)
- LVDS design guide (NS)
- An Overview of LVDS (NS AN-971)
- Transmission Line App guide (NS AN-905)
Here comes the usual disclaimer: These software and all the accompanying files are provided "as is" and without any warranties expressed or implied including but not limited to implied warranties of merchantability and fitness for a particular purpose. In no event should the author be liable for any damages whatsoever (including without limitation, damages for loss of business profits, business interruption, loss of business information, or any other pecuniary loss) arising out of the use or inability to use this product.