LT3681

VIN, RUN/SS Voltage..................36V
BOOST Pin Voltage...................56V
BOOST Pin Above SW Pin................30V
FB, RT, VC Voltage....................5V
BIAS, PG, BD Voltage..................30V
Maximum Junction Temperature .......... 125°C
DC above DA ......................40V
Operating Temperature Range (Note 2)
LT3681E..................40°C to 85°C
Storage Temperature Range  ...... 65°C to 150°C

The LT®3681 is an adjustable frequency (300kHz to 2.8MHz) monolithic buck switching regulator that accepts input voltages up to 34V (36V maximum). A high effi ciency 0.18 switch is included on the die along with a boost Schottky diode and the necessary oscillator, control, and logic circuitry. An undedicated power Schottky diode is integrated into the LT3681 to minimize the solution size. Current mode topology is used for fast transient response and good loop stability. Low ripple Burst Mode operation maintains high effi ciency at low output currents while keeping output ripple below 15mV in a typical application. In addition, the LT3681 can further enhance low output current effi ciency by drawing bias current from the output when VOUT is above 3V. Shutdown reduces input supply current to less than 1A while a resistor and capacitor on the RUN/SS pin provide a controlled output voltage ramp (soft-start). A power good fl ag signals when VOUT reaches 90% of the programmed output voltage. The LT3681 is available in 14-Pin 4mm x 3mm DFN package with exposed pads for low thermal resistance.