Impedance Controlled PCB
The impedance of a PCB trace is controlled by
- its configuration
- dimensions (trace width and thickness and
height of the board material)
- dielectric constant of the board material.
We can meet your requirement concerning all
these parameters.
- Printouts of Impedance Measurements;
- Impedance Coupons to Each Board;
- Impedance Measurements of Specific Traces;
- Characteristics and Differential Impedance.
Finished Impedance Tolerance:
Regular : +/-
10%;
Special :+/- 5%
Etch Factors per
side (mkm)
Cu Weights
(oz
) |
Internal
(+/-)
|
External
(+/-) |
1/4
|
0.25 |
1.30 |
1/2
|
1.30 |
2.54 |
1 |
25.00 |
50.00 |
2 |
50.00 |
75.00 |
3 |
75.00 |
100.00 |
4 |
100.00 |
125.00 |
You can find an additional information about impedance
calculation here (.xls 126Kb), and especial about differencial impedance
calculation here (.pdf 17Kb for more information see ref.4).
References
1. IPC-D-317A, "Design Guidelines for Electronic
Packaging Utilizing High-Speed Techniques," IPC, Chicago, 1995.
2. IPC-2141, "Controlled Impedance Circuit
Boards & High Speed Logic Design," IPC, Chicago, 1996.
3. IEC 61188-1-2, "Printed Boards and Printed
Board Assemblies—Design and Use. Part 1-2: Generic Requirements—Controlled
Impedance , " International Electrotechnical Commission, Geneva,
1998.
4. Douglas Brooks Columns, Articles, and Papers: www.ultracad.com/articles.htm |
