Parasitic inductance that exists in a package induces SSN (Simultaneous Switching Noise) and timing jitter. These noises cause malfunction of LSI and systems. The goal of this paper is to clarify the influence of the effective inductance of the package including mutual inductance by changing the number of simultaneously switching buffers and alternating adjacent buffers in the reverse direction each other. In this study, measured SSNs were reproduced by HSPICE simulation. The whole simulation model consisted of on-chip PDN (Power Distribution Network), package PDN and board PDN, along with I/O buffer model. The simulated SSN waveforms agreed well with the measured results.