SNLS622A July 2018 – December 2018 DSLVDS1001
PRODUCTION DATA.
As per the LVDS Application and Data Handbook (SLLD009), printed-circuit boards usually offer designers two transmission line options: microstrip and stripline. Microstrips are traces on the outer layer of a PCB, as shown in Figure 15.
On the other hand, striplines are traces between two ground planes. Striplines are less prone to emissions and susceptibility problems because the reference planes effectively shield the embedded traces. However, from the standpoint of high-speed transmission, juxtaposing two planes creates additional capacitance. TI recommends routing LVDS signals on microstrip transmission lines, if possible. The PCB traces allow designers to specify the necessary tolerances for ZO based on the overall noise budget and reflection allowances. Footnotes 1(2), 2(3), and 3(4) provide formulas for ZO and tPD for differential and single-ended traces. (2)(3)(4)