The LTC 3406B-1.2 is a high efficiency monolithic synchronous buck regulator using a constant frequency, current mode architecture. Supply current with no load is 300A dropping to <1A in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3406B-1.2 ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems. PWM pulse skipping mode operation provides very low output ripple voltage for noise sensitive applications.