MOSFET Driver delivers 5 A for buck/boost DC/DC converters.

Press Release Summary:



Operating from supplies up to 38 V, LTC4447 drives upper and lower power N-Channel MOSFET gates from rail-to-rail over 4-6.5 V range in synchronous rectified converter topology. It sinks up to 5 A, sources up to 3.2 A, and can also drive multiple MOSFETs in parallel for higher-current applications. Along with integrated bootstrap Schottky diode, features include adaptive shoot-through protection, 3-state PWM input, and separate input logic supply.



Original Press Release:



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



Milpitas, California (Southern) - June 30, 2008
MILPITAS, CA - June 30, 2008 - 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. Adaptive shoot-through protection is integrated to prevent both the upper and lower MOSFETs from conducting simultaneously while minimizing dead time.

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.

The LTC4447 is offered in a low profile (0.75mm) 3mm x 3mm DFN-12 package and operates over a -40°C to 85°C temperature range with prices starting at $1.35 for 1000-piece quantities.

SUMMARY OF FEATURES: LT C444
o Synchronous N-Channel MOSFET Driver
o High Drive Current - 3.2A Source, 5A Sink
o 38V Maximum Supply Voltage
o 4V to 6.5V Gate Drive Voltage
o Integrated Bootstrap Schottky Diode
o Adaptive Shoot-Through Protection
o Top Gate: 8ns Rise Time, 7ns Fall Time when driving 3000pF
o Bottom Gate: 7ns Rise Time, 4ns Fall Time When Driving 3000pF
o Three-State PWM Input for Power Stage Shutdown
o Rail-to-Rail Output Drivers

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