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Secondary-Side Synchronous Rectifier Driver
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LT8309
Secondary-Side
Synchronous Rectifier Driver
Features Description Works with DCM and BCM/CrCM Conduction Mode
Flyback Topologies
n V : 4.5V to 40V
CC
n Supports Up to 150V MOSFETs
n 26ns Turn-Off Propagation Delay
n Accurate Minimum On and Off Timers for Reliable
Operatio Adjustable and Accurate Trip Point: +5mV to –30mV
n 1Ω Gate Driver Pull-Dow SOT-23 5-Lead Package The LT®8309 is a secondary-side synchronous rectifier
driver that replaces the output rectifier diode in a flyback
topology. By replacing the diode with a N-channel MOSFET,
applications are no longer restricted by the heat constraints
of the output diode. The IC replicates the behavior of a
diode by sensing the drain-to-source voltage to determine
when the current becomes negative. The LT8309's low
minimum on-and off-times help improve noise immunity. n The fast propagation delay of 26ns allows applications to
operate in discontinuous conduction mode (DCM) and
critical conduction mode (CrCM). The gate driver features
a 0.8Ω pull-down device for fast turn-offs. The 40V VCC
rating allows the part to be driven from the output voltage or the rectified drain voltage of the MOSFET. A low …
