The LT?3990 is an adjustable frequency monolithic buck
switching regulator that accepts a wide input voltage
range up to 60V, and consumes only 2.5μA of quiescent
current. A high effi ciency switch is included on the die
along with the catch diode, boost diode, and the necessary
oscillator, control and logic circuitry. Low ripple Burst
Mode operation maintains high effi ciency at low output
currents while keeping the output ripple below 5mV in a
typical application. Current mode topology is used for fast
transient response and good loop stability. A catch diode
current limit provides protection against shorted outputs
and overvoltage conditions. An enable pin with accurate
threshold is available, producing a low shutdown current
of 0.7μA. A power good fl ag signals when VOUT reaches
90% of the programmed output voltage. The LT3990 is
available in small 10-pin MSOP and 3mm × 2mm DFN packages.