Features

• Wide Input Range: Operation from 3.6V to 58V
• Overvoltage Lockout Protects Circuits Through 80V Transients
• 2A Maximum Output Current
• Low Ripple (<15mV_P-P) Burst Mode® Operation: I_Q = 85μA at 12V_IN to 3.3V_OUT
• Adjustable Switching Frequency: 100kHz to 2.4MHz
• Low Shutdown Current: I_Q < 1μA
• Catch Diode Current Sense Protects Circuit Through Short-Circuit and Input Overvoltage
• Synchronizable Between 250kHz to 2MHz
• Power Good Flag
• Saturating Switch Design: 200mΩ On-Resistance
• Thermal Protection
• Soft-Start Capability
• Small 16-Pin Thermally Enhanced MSOP and 3mm × 4mm DFN Packages

Typical Application

Description

The LT®3980 is an adjustable frequency (100kHz to 2.4MHz) monolithic buck switching regulator that accepts input voltages up to 58V (80V transient). A high efficiency 200mΩ 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. Catch diode current sense (DA pin) protects the circuit during input voltage transients even when a high switching frequency is used. 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 LT3980 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 LT3980 is available in 16-pin MSOP and 3mm × 4mm DFN packages with exposed pads for low thermal resistance.