LT3976 Datasheet | Linear Technology

40V, 5A, 2MHz Step-Down Switching Regulator with 3.3µA Quiescent Current Features n Ultralow Quiescent Current: 3.3µA IQ at 12VIN to 3.3VOUT n Low Ripple Burst Mode® Operation Output Ripple < 15m VP-P n Wide Input Range: Operation from 4.3V to 40V n 5A Maximum Output Current n Excellent Start-Up and Dropout Performance n Adjustable Switching Frequency: 200k Hz to 2MHz n Synchronizable Between 250k Hz to 2MHz n Accurate Programmable Undervoltage Lockout n Low Shutdown Current: IQ = 700n A n Power Good Flag n Soft-Start Capability n Thermal Shutdown Protection n Current Limit Foldback with Soft-Start Override n Saturating Switch Design: 75mΩ On-Resistance n Small, Thermally Enhanced 16-Lead MSOP and 24-Lead 3mm × 5mm QFN Packages Applications n Automotive Battery Regulation n Portable Products n Industrial Supplies L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Description The LT®3976 is an adjustable frequency monolithic buck switching regulator that accepts a wide input voltage range up to 40V. Low quiescent current design consumes only 3.3µA 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 15m V in a typical application. The LT3976 can supply up to 5A of load current and has current limit foldback to limit power dissipation during short-circuit. A low dropout voltage of 500m V is maintained when the input voltage drops below the programmed output voltage, such as during automotive cold crank. An internally pensated current mode topology is used for fast transient response and good loop stability. A high efficiency 75mΩ switch is included on the die along with a boost Schottky diode. An accurate 1.02V threshold enable pin can be driven directly from a microcontroller or used as a programmable...