LT8643S 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 96% Efficiency at 1MHz, 12V_IN to 5V_OUT
  • Up to 95% Efficiency at 2MHz, 12V_IN to 5V_OUT
• Wide Input Voltage Range: 3.4V to 42V
• 6A Maximum Continuous, 7A Peak Output
• Ultralow Quiescent Current Burst Mode^® Operation
  • Output Ripple < 10mV_P-P
• External Compensation: Fast Transient Response and Current Sharing
• Fast Minimum Switch On-Time: 30ns
• Low Dropout Under All Conditions: 100mV at 1A
• Forced Continuous Mode
• Adjustable and Synchronizable: 200kHz to 3MHz
• Output Soft-Start and Tracking
• Small 24-Lead 4mm × 4mm LQFN Package
• AEC-Q100 Qualified for Automotive Applications

• Automotive and Industrial Supplies
• General Purpose Step-Down

The LT8643S 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 reducing layout sensitivity. This performance makes the LT8643S ideal for noise-sensitive applications and environments.

Peak current mode control with a 30ns minimum on-time allows high step-down ratios even at high switching frequencies. The LT8643S has external compensation to enable current sharing and fast transient response at high switching frequencies.

Burst Mode operation enables ultralow standby current consumption, forced continuous mode can control frequency harmonics across the entire output load range, or spread spectrum operation can further reduce EMI emissions.