LT8641A Datasheet

• Silent Switcher^® Architecture
  • Ultralow EMI Emissions
  • Spread Spectrum Frequency Modulation
• High Efficiency at High Frequency
  • Up to 95% Efficiency at 1MHz, 12V_IN to 5V_OUT
  • Up to 94% Efficiency at 2MHz, 12V_IN to 5V_OUT
• Wide Input Voltage Range: 3V to 65V
• 3.5A Maximum Continuous, 5A Peak Transient Output
• Ultralow Quiescent Current Burst Mode^® Operation
  • 2.5μA I_Q Regulating 12V_IN to 3.3V_OUT
  • Output Ripple < 10mV_P-P
• Fast Minimum Switch On-Time: 35ns
  • True 2MHz Operation for 24V_IN Systems
• Low Dropout Under All Conditions: 130mV at 1A
• Safely Tolerates Inductor Saturation in Overload
• Adjustable and Synchronizable: 200kHz to 3MHz
• Output Soft-Start and Tracking
• Small 18-Lead 3mm × 4mm Side Wettable QFN with Improved Solder Joint Reliability
• AEC-Q100 Qualified for Automotive Applications

• Automotive and Industrial Supplies
• General Purpose Step-Down

The LT8641A step-down regulator features Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at frequencies up to 3MHz. Assembled in a 3mm × 4mm side wettable QFN, the monolithic construction with integrated power switches and inclusion of all necessary circuitry yields a solution with a minimal PCB footprint. An ultralow 2.5μA quiescent current — with the output in full regulation — enables applications requiring highest efficiency at very small load currents. Transient response remains excellent and output voltage ripple is below 10m_VP-P at any load, from zero to full current.

The LT8641A allows high V_IN to low V_OUT conversion at high frequency with a fast minimum top switch on-time of 35ns. Operation is safe in overload even with a saturated inductor.

Essential features are included and easy to use: an open-drain PG pin signals when the output is in regulation. The SYNC/MODE pin selects between Burst Mode, pulse-skipping, or spread spectrum mode, and also allows synchronization to an external clock. Soft-start and tracking functionality are accessed through the TR/SS pin. An accurate enable threshold can be set using the EN/UV pin and a resistor at the RT pin programs switch frequency.