Features

• Wide Input Range:
  Operation from 3.6V to 33V
  Over-Voltage Lockout Protects Circuits
  Through 62V Transients
• 3.5A Maximum Output Current
• Low Ripple (<15mV_P-P) Burst Mode® Operation: I_Q= 75μA at 12V_IN to 3.3V_OUT
• Adjustable Switching Frequency: 200kHz to 2.4MHz
• Low Shutdown Current: I_Q < 1μA
• Integrated Boost Diode
• Synchronizable Between 250kHz to 2MHz
• Power Good Flag
• Saturating Switch Design: 95mΩ On-Resistance
• Output Voltage: 0.79V to 30V
• Thermal Protection
• Soft-Start Capability
• Small 10-Pin Thermally Enhanced MSOP and (3mm × 3mm) DFN Packages

Typical Application

Description

The LT3972 is an adjustable frequency (200kHz to 2.4MHz) monolithic buck switching regulator that accepts input voltages up to 33V (62V Maximum). A high efficiency 95mΩ switch is included on the die along with a boost Schottky diode and the necessary oscillator, control, and logic circuitry. Current mode topology is used for fast transient response and good loop stability. Low ripple Burst Mode operation maintains high efficiency at low output currents while keeping output ripple below 15mV in a typical application. In addition, the LT3972 can further enhance low output current efficiency by drawing bias current from the output when V_OUT is above 3V Shutdown reduces input supply current to less than 1μA while a resistor and capacitor on the RUN/SS pin provide a controlled output voltage ramp (soft-start). A power good flag signals when V_OUT reaches 91% of the programmed output voltage. The LT3972 is available in 10-Pin MSOP and 3mm × 3mm DFN packages with exposed pads for low thermal resistance.