Sensirion provides detailed information on both the package outline and the land pattern. In fact, it is recommended, because the IC pad pitch is just 0.5 mm, that only one solder mask opening should be used for all four pads on one side. It is also suggested, when using solder paste printing, that a laser-cut stainless steel stencil with trapezoidal walls and with a stencil thickness of 0.1 or 0.125 mm should be used. See the images below. This information should be quite helpful for a PCB layout design team.
It’s always good to be cognizant of trace lengths when you’re laying out a parallel bus, though at moderate frequencies it is nothing to stress about. The propagation time for a signal traveling through a trace is maybe 150 picoseconds/inch. So if you have two traces with a length mismatch of one inch, one signal will arrive 150 ps after the other signal. If your signals are transitioning at a frequency whose corresponding period is much greater than 150 ps, this one-inch mismatch won’t cause problems. Even at 100 MHz (which is pretty fast for a parallel bus), the period is 10 ns, i.e., ~67 times larger than the time-of-arrival discrepancy for a one-inch mismatch.
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