This blog presents the most common design issues affecting signal integrity in high-speed digital hardware design. These include impedance control, terminations, ground/power planes, signal routing and crosstalk. Armed with the knowledge presented here, a digital designer will be able to recognize potential signal integrity problems at the earliest design stage. Also, they will be able to apply techniques presented to prevent these issues affecting the performance of their design.
IntroductionSuperSpeed USB (USB 3.0) delivering data rates up to 5Gbps which is ten times faster than Hi-Speed USB (USB 2.0) with optimized power efficiency. At these high transmission rates, signal integrity issues become increasingly restrictive on PCB trace and cable lengths, and on design implementation and features. Poor signal quality can significantly impact system performance and reliability.SuperSpeed (USB 3.0) ReDriver in Source ApplicationSuperspeed is a dual channel (TX± and RX±),
Capacitive sensing is the art of measuring a relatively very small variation of capacitance in a noisy environment.
To illustrate the principle of capacitive sensing we will use the typical simplest button implementation below but the same basic laws apply to more complex capacitive structures like sliders or wheels.
Figure shows cut view and top view of a typical capacitive button implementation. The sensor connected is a simple round copper area on top layer of the PCB. I
Similarly to the mechanical buttons they intend to replace, touch buttons provide ON/OFF information i.e. respectively button touched or not touched by the finger. Each touch button is associated to its dedicated capacitive sensor.
Round is best while oval or square with round corners are also acceptableAny other shape with acute angles is not recommendedPossibility to put a hole for reverse mount SMD LED in the middle (will reduce a little bit the sensor surface, c