The ISL80030, ISL80030A, ISL80031, and ISL80031A are highly efficient, monolithic, synchronous step-down DC/DC converters that can deliver up to 3A of continuous output current from a 2. 7V to 5. 5V input supply. They use peak current mode control architecture to allow very low duty cycle operation. These devices operate at either a 1MHz or 2MHz switching frequency, thereby providing superior transient response and allowing for the use of small inductors. They also have excellent stability. The ISL80030, ISL80030A, ISL80031, and ISL80031A integrate very low rDS(ON)MOSFETs to maximize efficiency. In addition, because the high-side MOSFET is a PMOS, the need for a Boot capacitor is eliminated, thereby reducing external component count. The devices can operate at 100% duty cycle. The ISL80030 and ISL80030A are configured for PWM pulse width modulation operation and provide a fast transient response, which helps reduce the output noise and RF interference. The ISL80031 and ISL80031A are configured for PFM discontinuous conduction operation and provide high efficiency by reducing switching losses at light loads. These devices are offered in a space saving 8 Ld 2mmx2mm DFN Pb-free package with exposed pad for improved thermal performance. The complete converter occupies less than 64mm2area.