Features

• Wide Input Voltage Range: 3.0V to 42V
• Ultralow Quiescent Current Burst Mode® Operation:
  <2.5μA I_Q Regulating 12V_IN to 3.3V_OUT
  Output Ripple <10mV_P-P
• High Efficiency 2MHz Synchronous Operation:
  >93% Efficiency at 1A, 5V_OUT from 12V_IN
• 2A Maximum Continuous Output, 3A Peak Transient Output
• Fast Minimum Switch-On Time: 45ns
• Adjustable and Synchronizable: 200kHz to 2.2MHz
• Spread Spectrum Frequency Modulation for Low EMI
• Allows Use of Small Inductors
• Low Dropout
• Peak Current Mode Operation
• Accurate 1V Enable Pin Threshold
• Internal Compensation
• Output Soft-Start and Tracking
• Small 10-Lead MSOP Package

Typical Application

Description

The LT®8609/LT8609A/LT8609B is a compact, high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 1.7μA of non-switching quiescent current. The LT8609/LT8609A/LT8609B can deliver 2A of continuous current with peak loads of 3A (<1sec). Burst Mode operation enables high efficiency down to very low output currents while keeping the output ripple below 10mV_P-P. A SYNC pin allows synchronization to an external clock, or spread spectrum modulation for low EMI operation. Internal compensation with peak current mode topology allows the use of small inductors and results in fast transient response and good loop stability. The EN/UV pin has an accurate 1V threshold and can be used to program V_IN UVLO or to shut down the part. A capacitor on the TR/SS pin programs the output voltage ramp rate during start-up while the PG flag signals when V_OUT is within ±8.5% of the programmed output voltage as well as fault conditions. The LT8609A has slower switch edges for lower EMI emissions. The LT8609B operates in pulse-skipping mode only.