High efficiency synchronous regulator LTC4449: High Speed Synchronous N-Channel MOSFET Driver
Linear Technology Corporation introduces the LTC4449, 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 one of Linear Technology's DC/DC controllers and power FETs forms a complete high efficiency synchronous regulator that can be used as a step-down or step-up DC/DC converter. The LTC4449 drives both upper and lower MOSFET gates over a range of 4V to 6.5V and operates from a supply voltage up to 38V. This powerful driver can sink up to 4.5A and source up to 3.2A, making it ideal for driving high gate capacitance and high current MOSFETs. It can also drive multiple MOSFETs in parallel for higher current applications. The 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. Adaptive shoot-through protection is integrated to prevent the upper and lower MOSFETs from conducting simultaneously while minimizing dead time. The LTC4449 features a 3-state pulse with modulation (PWM) input for power stage control and shutdown that is compatible with all multiphase controllers employing a 3-state output feature. In addition, the LTC4449 has a separate supply for the input logic to match the signal swing of the controller IC, as well as an undervoltage lockout circuit on both the driver and logic supplies. The LTC4449EDCB is available in a 2mm x 3mm DFN-8 package. The Industrial grade version, LTC4449IDCB, is guaranteed to operate over a -40ºC to 125ºC operating junction temperature range and is available from stock.
Summary of Features: LTC4449
Synchronous N-Channel MOSFET Driver
4V to 6.5V Gate Drive VCC Voltage
38V Maximum Supply Voltage
Adaptive Shoot -Through Protection
Three-State PWM Input for Power Stage Control
High Drive Current - 3.2A Source, 4.5A Sink
Top Gate: 8ns Rise Time, 7ns Fall Time when Driving 3000pF
Bottom Gate: 7ns Rise Time, 4ns Fall Time when Driving 3000pF
