LT3973-5

FEATURES nn Ultralow Quiescent Current nn 2.5µA IQ at 12VIN to 3.3VOUT nn Low Ripple Burst Mode® Operation nn Output Ripple < 10mVP-P nn Wide Input Voltage Range: 4.2V to 42V Operating nn Adjustable Switching Frequency: 200kHz to 2.2MHz nn Integrated Boost and Catch Diodes nn 750mA Output Current nn Excellent Start-Up and Dropout Performance nn Fixed Output Voltages: 3.3V, 5V nn 1.9µA IQ at 12VIN nn Accurate Programmable Undervoltage Lockout nn Low Shutdown Current: IQ = 0.75µA nn Internal Catch Diode Current Limit nn Power Good Flag nn Thermal Shutdown nn Small, Thermally Enhanced 10-Lead MSOP and (3mm × 3mm) DFN Packages APPLICATIONS nn Automotive Battery Regulation nn Power for Portable Products nn Industrial Supplies nn Gate Drive Bias LT3973/LT3973-3.3/LT3973-5 42V, 750mA Step-Down Regulator with 2.5µA Quiescent Current and Integrated Diodes DESCRIPTION The LT®3973 is an adjustable frequency monolithic buck switching regulator that accepts a wide input voltage range 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 currents while keeping the output ripple below 10mV in a typical application. A minimum dropout voltage of 530mV is maintained when the input voltage drops below the programmed output voltage, such as during automotive cold crank. Curre...