This application note presents an easy-to-use frequency calculator for determining the proper ordering option, discrete bias resistor selection, and input settings for the DS1090 low-frequency, resistor-programmable, spread-spectrum EconOscillator. The DS1090 is capable of generating a spread-spectrum, square wave output between 125kHz and 8MHz. This spread-spectrum system function is important when EMI is a concern for the end application, such as a switched-mode power supply.