MAX9485 is a versatile, programmable, audio clock generator. It consists of a VCXO, fractional-N PLL, and I2C interface. To use the MAX9485 appropriately, it is important that the power level of the VCXO’s crystal does not exceed its maximum rating. This application note describes a simple method for measuring the power level of a crystal oscillator, and reports the test results on the MAX9485.