Hi,
I am working on a small carrier card for TE0714-04-52I-7-B for which I am placing U.FL connectors on all lanes.
Since this is my first HS card, I would like to have some guideline regarding differential traces length and impedance.
As far as I know the theoretical differential impedance should be 100 ohm with 50 ohm for each trace.
I can inspect Simple base of TE0714 through Altium online viewer using AP-TEBB0714-01.zip, so the lengths on the simple base are known.
What are the GTP lanes length on TE0714-04-52I-7-B and what are the computed impedances (differential, even and odd) for the overall design, so to keep these values as reference?
Thanks,
s.
I mainly ask because attempting to compute impedance for the differential lanes according to the stackup of Simple Base TE0714:
SIMPLE_BASE_TE0714_STACKUP.png
I obtain results far from the 100 ohm differential and 50 ohm even/odd (I account that maybe is quiet difficult to obtain nearly exact results):
KICAD_DIFF_Z_CAL.png
Computation algorithms used are:
Coupled microstrip line:
- A. Atwater, "Simplified Design Equations for Microstrip Line Parameters", Microwave Journal, pp. 109-115, November 1989.
- Kirschning and R. H. Jansen, "Accurate Wide-Range Design Equations for the Frequency-Dependent Characteristic of Parallel Coupled Microstrip Lines," in IEEE Transactions on Microwave Theory and Techniques, vol. 32, no. 1, pp. 83-90, Jan. 1984. doi: 10.1109/TMTT.1984.1132616.
- Jansen, "High-Speed Computation of Single and Coupled Microstrip Parameters Including Dispersion, High-Order Modes, Loss and Finite Strip Thickness", IEEE Trans. MTT, vol. 26, no. 2, pp. 75-82, Feb. 1978.
- March, "Microstrip Packaging: Watch the Last Step", Microwaves, vol. 20, no. 13, pp. 83.94, Dec. 1981.
According to KiCAD docs: https://docs.kicad.org/9.0/en/pcb_calculator/pcb_calculator.html
Thanks again for any support.
GTP trace signal length are between 18 and 24 mm on the TE0714
as of signals on TEBB0714 I just recalculated the differential impedance and got 100.16 ohms. But there are many calculators available all delivering somewhat different results.Altium layerstack is not updated with real layerstack params in this project so that makes small difference in the calculations, with altium layerstack params the differenial impedance is 109 ohms.