Method and system for voltage fluctuation amount calculation

A voltage fluctuation amount calculation system for calculating fluctuation amount of power supply voltage in a semiconductor device corresponding to a mounting manner of a decoupling capacitor mounted on a power supply input unit to the semiconductor device, the system comprising:

• an internal circuit for being disposed over the semiconductor device in the semiconductor device and for detecting the power supply voltage fluctuation generated in the semiconductor device, the fluctuation of the power supply voltage being detected by being stuck of the internal circuit;
• a storage unit for storing first relationship between the power supply voltage supplied to the semiconductor device through the power supply input unit and maximum operable frequency of the internal circuit upon the fluctuation of the power supply voltage being detected by changing the power supply voltage and operating frequency of the internal circuit, and storing second relationship between the maximum operable frequency of the internal circuit and the mounting manner of the decoupling capacitor upon the fluctuation of the power supply voltage being detected by changing the mounting manner of the decoupling capacitor and the operating frequency of the internal circuit;
• and
• a voltage fluctuation amount calculation unit for specifying the power supply voltage in the semiconductor device corresponding to the mounting manner of the decoupling capacitor based on the first relationship and the second relationship, and calculating the fluctuation amount from predetermined power supply voltage based on the specified power supply voltage.