LT8645S Datasheet

• Silent Switcher^® 2 Architecture 
  • Ultralow EMI Emissions on Any PCB
  • Eliminates PCB Layout Sensitivity
  • Internal Bypass Capacitors Reduce Radiated EMI 
  • Optional Spread Spectrum 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: 3.4V to 65V
• Ultralow Quiescent Current Burst Mode Operation
  • 2.5μA I_Q Regulating 12V_IN to 3.3V_OUT (LT8645S) 
  • Output Ripple < 10mV_P-P
• Fast Minimum Switch On-Time: 40ns
• Low Dropout Under All Conditions: 60mV at 1A
• Adjustable and Synchronizable: 200kHz to 2.2MHz
• Peak Current Mode Operation 
• Output Soft-Start and Tracking
• Small 32-Lead 6mm × 4mm LQFN Package
• AEC-Q100 Qualified for Automotive Applications

• Automotive and Industrial Supplies
• General Purpose Step-Down
• GSM Power Supplies

The LT8645S synchronous step-down regulator features second generation Silent Switcher architecture designed to minimize EMI emissions while delivering high efficiency at high switching frequencies. This includes the integration of bypass capacitors to optimize all the fast current loops inside and make it easy to achieve advertised EMI performance by eliminating layout sensitivity.

The fast, clean, low-overshoot switching edges enable high efficiency operation even at high switching frequencies, leading to a small overall solution size. Peak current mode control with a 40ns minimum on-time allows high step-down ratios even at high switching frequencies.

Burst Mode^® operation enables ultralow standby current consumption, pulse-skipping mode allows full switching frequency at lower output loads, or spread spectrum operation can further reduce EMI emissions.