DESCRIPTION
The LT4322 is a floating active rectifier controller that
drives an external N-Channel MOSFET to replace a
rectifier diode. It is designed primarily for AC
applications and operates with input supply frequencies
ranging from DC to 100kHz. On each cycle of the input
AC waveform, an external N-Channel MOSFET gate is
enhanced to provide the equivalent of a low diode
forward voltage drop of 25mV. The resulting reduction
in power dissipation eliminates thermal design
problems and costly heat sinks, greatly reducing PC
board area.
The addition of a high-voltage depletion N-Channel
MOSFET enables operation at very high output voltages,
limited only by the voltage ratings of two external
MOSFETs. In AC applications, an integrated LDO
provides the required gate drive voltage to turn the
external MOSFET fully on. Fast, high-current gate drivers
minimize reverse current transients at high input frequencies.

FEATURES
 Replaces Rectifying Diodes with N-Channel
MOSFETs in Rectifier Applications
 Maximizes Power Efficiency, Eliminates Thermal
Design Problems
 Low 25mV Forward Voltage Drop
 Wide Operating Voltage Range: 9V to >500V
 Wide Operating Frequency Range: DC to 100kHz
 Regulated 12V GATE Drive for External N-Channel
MOSFET Enhancement
 8-Lead MSOP and 8-Lead, 3mm x 3mm, Side Wettable
DFN Packages

APPLICATIONS
 Single-Phase, 3-Phase, and 6-Phase Bridge
Rectifiers
 Automotive Alternator Bridge Rectifiers
 Off-Line Active Bridge Rectifier
 3-Phase Aircraft Power
 High-Voltage DC Diode-OR with Reverse Blocking