LT8642S 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 3.3V_OUT
  • Up to 95% Efficiency at 2MHz, 12V_IN to 3.3V_OUT
• Wide Input Voltage Range: 2.8V to 18V
• 10A Output Current
• External Compensation: Fast Transient Response and Current Sharing
• Low Quiescent Current Burst Mode^® Operation
  • 240µA IQ Regulating 12V_IN to 1.2V_OUT
  • Output Ripple < 10mV_P-P
• Fast Minimum Switch On-Time: 25ns
• Low Dropout Under All Conditions: 50mV at 1A
• Forced Continuous Mode
• Adjustable and Synchronizable: 200kHz to 3MHz
• Output Soft-Start and Power Good
• Small 24-Lead 4mm × 4mm LQFN Package

• Server Power Applications
• Automotive and Industrial Supplies
• General Purpose Step-Down

The LT8642S 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 20ns minimum on-time allows high step down ratios even at high switching frequencies. External compensation via the V_C pin allows for fast transient response at high switching frequencies. A CLKOUT pin enables synchronizing other regulators to the LT8642S.

Burst Mode operation enables low 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. Soft-start and tracking functionality is accessed via the SS pin, and an accurate input voltage UVLO threshold can be set using the EN/UV pin.