Patent ID: 8214785
Filing Date: 2012-07-03
Classification: G06F

Abstract:
1. A method of estimating simultaneous switching noise that is caused by simultaneously switching an input/output signal of a plurality of pins in a semiconductor device, the method being realized by using a computer executing a process of: obtaining, by using the computer, a number of simultaneous switching signals of a first input/output signal and a number of simultaneous switching signals of a second input/output signal by using pin information that the plurality of pins in the semiconductor device are associated with user setting information for determining the input/output signal for each of the pins; obtaining, by using the computer, a first noise value corresponding to a number A of simultaneous switching signals of the first input/output signal using a first user setting information that cause the largest noise, a second noise value corresponding to a number of A+B obtained by adding noise cause by a number B of switching signals of the second input/output using a second user setting information causing the second largest noise and the noise of the number A of simultaneous switching signals of the first input/output signal using the second user setting information; calculating, by using the computer, a difference between the noise value corresponding to the number A+B of simultaneous switching signals and the noise value corresponding to the number A of simultaneous switching signals of the second input/output signal as a simultaneous switching noise value of the second input/output signal by using the noise information; calculating, by using the computer, a sum of the noise value corresponding to the number A of simultaneous switching signals of the first input/output signal and the simultaneous switching noise value of the second input/output signal as an estimate of simultaneous switching noise of a pin in the semiconductor device; wherein pins arranged in a neighborhood of a process-target pin are categorized into a plurality of groups, and the numbers of the simultaneously switching signals are obtained respectively in the obtaining the number of simultaneous switching signal; the difference calculation is executed, for each group of the simultaneously switching signals obtained for each set of user setting information; and simultaneous switching noise is calculating a sum of the difference obtained for each set of user setting information and for each group in the noise sum calculation.