DESCRIPTION
The LT®3971 is an adjustable frequency monolithic buck switching regulator that accepts a wide input voltage range up to 38V. Low quiescent current design consumes only 2.8µA of supply current while regulating with no load. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping the output ripple below 15mV in a typical application. An internally compensated current mode topology is used for fast transient response and good loop stability. A high efficiency 0.33Ω switch is included on the die along with a boost Schottky diode and the necessary oscillator, control and logic circuitry.

FEATURES
■ Ultralow Quiescent Current:
   2.8µA IQ Regulating 12VIN to 3.3VOUT
■ Fixed Output Voltages: 3.3V, 5V,
   2.1µA IQ Regulating 12VIN to 3.3VOUT
■ Low Ripple Burst Mode® Operation:
   Output Ripple < 15mVP-P
■ Wide Input Voltage Range: 4.3V to 38V
■ 1.2A Maximum Output Current
■ Adjustable Switching Frequency: 200kHz to 2MHz
■ Synchronizable Between 250kHz to 2MHz
■ Fast Transient Response
■ Accurate 1V Enable Pin Threshold
■ Low Shutdown Current: IQ = 700nA
■ Power Good Flag
■ Soft-Start Capability
■ Internal Compensation
■ Output Voltage: 1.19V to 30V
■ Small Thermally Enhanced 10-Lead MSOP, 16-Lead
   MSOP and (3mm × 3mm) DFN Packages

APPLICATIONS
■ Automotive Battery Regulation
■ Power for Portable Products
■ Industrial Supplies