IFX90121 2.2MHz Step-Down Regulator Infineon IFX90121 2.2MHz Step-Down Regulator is a high frequency PWM step-down DC/DC converter with a wide input voltage range from 4.75V to 45V that makes the IFX90121 suitable for a wide variety of applications. The switching frequency of 2.2MHz allows the use of small inductors and capacitors, resulting in minimized board space. Pulse Frequency Modulation is used to optimize efficiency in light load conditions. The low quiescent current in shutdown (less than 45μA at nominal input voltage) makes the device suitable for battery powered systems. Additional applications include smart metering and general purpose industrial.