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High Speed Synchronous N-Channel MOSFET Driver Delivers 5A for High Efficiency Buck or Boost DC/DC Converters

Linear Technology Corporation introduces the LTC4447, a high speed synchronous MOSFET driver designed to drive upper and lower power N-Channel MOSFETs in a synchronous rectified converter topology. This driver, combined with power MOSFETs and one of Linear Technology's DC/DC controllers, forms a complete high efficiency synchronous regulator that can be used as a step-down or step-up DC/DC converter.


The LTC4447 drives both upper and lower MOSFET gates from rail-to-rail over a voltage range of 4V to 6.5V and operates from a supply voltage up to 38V. This powerful driver can sink up to 5A and source up to 3.2A, making it ideal for driving high gate capacitance, high current MOSFETs. The LTC4447 can also drive multiple MOSFETs in parallel for higher current applications and it includes an integrated bootstrap schottky diode. The very fast 8ns rise time, 7ns fall time of the top MOSFET and 7ns rise time, 4ns fall time of the bottom MOSFET, when driving a 3,000pF load, minimize switching losses and improve efficiency.

The LTC4447 has a 3-state PWM input for power stage shut-down that is compatible with single and multi-phase controllers employing a 3-state output feature. In addition, it has a separate supply for the input logic to match the signal swing of the controller IC and undervoltage lockout circuits on both the driver and logic supplies.

 Synchronous MOSFET Driver for DC/DC Converters

Summary of Features: LTC4447
Synchronous N-Channel MOSFET Driver
High Drive Current - 3.2A Source, 5A Sink
38V Maximum Supply Voltage
4V to 6.5V Gate Drive Voltage
Integrated Bootstrap Schottky Diode
Adaptive Shoot-Through Protection
Top Gate: 8ns Rise Time, 7ns Fall Time when driving
Bottom Gate: 7ns Rise Time, 4ns Fall Time When Driving
Three-State PWM Input for Power Stage Shutdown
Rail-to-Rail Output Drivers


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