The LTC1771 is a high efficiency current mode stepdown DC/DC controller that draws as little as 10A DC supply current to regulate the output at no load while maintaining high efficiency for loads up to several amps. The LTC1771 drives an external P-channel power MOSFET using a current mode, constant off-time architecture. An external sense resistor is used to program the operating current level. Current mode control provides short-circuit protection, excellent transient response and controlled start-up behavior. Burst Mode operation enables the LTC1771 to maintain high efficiency down to extremely low currents. Shutdown mode further reduces the supply current to a mere 2A. For low noise applications, Burst Mode operation can be easily disabled with the MODE pin.