This paper presents an assessment of jitter induced by power and ground (P/G) voltage variations. The assessment is based on an extended input/output buffer information specification (IBIS)-like model for capturing the effect of P/G signal variations under simultaneous switching output (SSO) buffers. The requirements of nonlinear modeling for the accurate prediction is explained and illustrated. The implemented large signal equivalent-circuit model is validated under different test conditions having different P/G voltage variations for predicting the output signal distortions. The associated jitter analysis by predicting the eye diagram under the noise conditions is performed. The maximum values of the prediction error for the peak to peak values of eye jitter and eye height are 7.06% and 2.59%, respectively. © 2019 IEEE.