Study of Power Supply Impedance Using Electromagnetic Field Simulator

Study of power supply impedance using S-NAP/Field

In the power supply and ground pattern shown in Fig. 4, we remove the IC as shown in Fig. 5 and set a port at the IC's power terminal, then simulate the impedance from that port. The power supply terminal (the port section in Fig. 4) is connected to ground. Fig. 5 shows the current distribution at 225 MHz. As shown in Fig. 6, resonance is observed around 240 MHz, and at this frequency, it can be seen that current is already concentrated on the power input terminal side (the left end of the pattern). 【Features】 ○ Fig. 6 shows the impedance characteristics from 10 MHz to 500 MHz. ○ As is clear from the Smith chart, it demonstrates the characteristics of a transmission line with a short-circuited end. ○ The impedance reaches its maximum around 240 MHz, indicating that resonance occurs at this frequency (λ/4 resonance of the short-circuited stub). For more details, please contact us or download the catalog.

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