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Modern electronics products must have improved characteristics, including high-speed, high-density, and lowervoltage operations. With such designs, a poor PCB (printed circuit board) layout in the signal integrity (SI) system is affected by the noise and becomes unstable. Crosstalk is a major noise that interferes with SI. Generally, a guard trace is added between Victim and the other the Aggressor to prevent crosstalk. Two grounded vias are added between two ends of this guard trace, respectively, for reducing crosstalk. With the working frequency being higher and higher, crosstalk interferes more and more serious. Even, this guard trace will be as one noise source to affect Victim. In this paper, we present the effects of a guard trace with the optimal number of grounded vias that gives the maximum efficiency for preventing crosstalk in parallel double micro-strip lines in a high-speed PCB layout. In comparison with a guard trace with two terminal grounded vias, our swing of the near-end crosstalk is its 37%, and our swing of far-end crosstalk is its 45%.

This paper presents the design flow of two high-efficiency class-E amplifiers for the implantable electrical stimulation system. The implantable stimulator is a high-Q class-E driver that delivers a sine-wave pulsed radiofrequency (PRF) stimulation, which was verified to have a superior efficacy in pain relief to a square wave. The proposed duty-cycle-controlled class-E PRF driver designed with a high-Q factor has two operational modes that are able to achieve 100% DC-AC conversion, and involves only one switched series inductor and an unchanged parallel capacitor. The measured output amplitude under low-voltage (LV) mode using a 22% duty cycle was 0.98 V with 91% efficiency, and under high-voltage (HV) mode using a 47% duty cycle was 2.95 V with 92% efficiency. These modes were inductively controlled by a duty-cycle detector, which can detect the duty-cycle modulated signal generated from the external complementary low-Q class-E power amplifier (PA). The design methodology of the low-Q inductive interface for a non-50% duty cycle is presented. The experimental results exhibits that the 1.5-V PA that consumes DC power of 14.21 mW was able to deliver a 2.9-V sine wave to a 500 Ω load. The optimal 60% drain efficiency of the system from the PA to the load was obtained at a 10-mm coupling distance.

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