A constant-frequency, current-mode architecture allows a selectable fixed or phase-locked loop (PLL) frequency from 250kHz to 750kHz . Output current sensing is accomplished by measuring the voltage drop across the output inductor (DCR) or using an optional sense resistor. Current foldback limits MOSFET heat dissipation during short circuit and overload conditions. Selectable continuous, pulse skipping or Burst Mode® operation is user controlled to optimize light load efficiency. With up to 99% duty cycle, the LTC3851A/-1 has a very low dropout voltage, a useful feature for extending run times in battery powered applications. Additional features include tracking and adjustable soft-start. The LTC3851A-1 differs from the LTC3851A in that it has a power good signal instead of adjustable current limit.
The LTC3851AH/-1 and LTC3851AMP/-1 are available in a thermally enhanced MSOP-16 package. The 1000-piece price starts at $2.24 each for the H-grade devices and $5.29 each for the MP-grade parts, respectively. For more information, visit www.linear.com/product/LTC3851A
Summary of Features: LTC3851A/-1
• VIN Range from 4V to 38V
• Strong Onboard N-Channel MOSFET Driver
• Current-Mode Control
• DCR or RSENSE Current Sense Options
• Programmable Current Limit Threshold Voltage
• Phase-Locked-Loop Synchronization
• Adjustable Soft-Start or Tracking
• Power Good Signal
• Fixed Operating Frequency or Synchronizable from 250kHz to 750kHz