DESCRIPTION
The LT®3973 is an adjustable frequency monolithic buck switchingregulatorthatacceptsawideinputvoltagerange up to 42V, and consumes only 2.5µA of quiescent current. A high efficiency 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 efficiency at low output current swhile keeping the output ripple below 10mV in a typical application.

FEATURES
■ Ultralow Quiescent Current
   ■ 2.5µA IQ at 12VIN to 3.3VOUT
■ Low Ripple Burst Mode® Operation
   ■ Output Ripple < 10mVP-P
■ Wide Input Voltage Range: 4.2V to 42V Operating
■ Adjustable Switching Frequency: 200kHz to 2.2MHz
■ Integrated Boost and Catch Diodes
■ 750mA Output Current
■ Excellent Start-Up and Dropout Performance
■ Fixed Output Voltages: 3.3V, 5V
   ■ 1.9µA IQ at 12VIN
■ Accurate Programmable Undervoltage Lockout
■ Low Shutdown Current: IQ = 0.75µA
■ Internal Catch Diode Current Limit
■ Power Good Flag
■ Thermal Shutdown
■ Small, Thermally Enhanced 10-Lead MSOP and (3mm × 3mm) DFN Packages

APPLICATIONS
■ Automotive Battery Regulation
■ Power for Portable Products
■ Industrial Supplies
■ Gate Drive Bias