Features

• Wide Input Range:
  Operation from 3.6V to 36V
  Overvoltage Lockout Protects Circuits through
  60V Transients
• 1A Output Current
• Low Ripple Burst Mode® Operation
  I_Q = 75μA at 12V_IN to 3.3V_OUT
  Output Ripple < 15mV_P-P
• Adjustable Switching Frequency: 250kHz to 2.2MHz
• Short-Circuit Protected
• Synchronizable Between 300kHz and 2.2MHz
• 0.8V Feedback Reference Voltage
• Output Voltage 0.8V to 20V
• Soft-Start Capability
• Power Good Flag
• Small 12-Pin Thermally Enhanced 3mm × 3mm DFN Package

Typical Application

Description

The LT3682 is an adjustable frequency (250kHz to 2.2MHz) monolithic buck switching regulator that accepts input voltages up to 36V. A high efficiency 0.5Ω switch is included on the device along with a boost diode and the necessary oscillator, control, and logic circuitry. Current mode topology is used for fast transient response and good loop stability. A SYNC pin allows the user to synchronize the part to an external clock, and to choose between Low Ripple Burst Mode operation and standard PWM operation.

The Low Ripple Burst Mode maintains high efficiency at low output currents while keeping output ripple below 15mV in typical applications. 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 90% of the programmed output voltage. Protection circuitry senses the current in the power switch and external Schottky catch diode to protect the LT3682 against short-circuit conditions. Frequency foldback and thermal shutdown provide additional protection.

The LT3682 is available in a 12-Pin 3mm × 3mm DFN with exposed pad for low thermal resistance.