LT8309 Series

Secondary-Side Synchronous Rectifier Driver

Catalog

Secondary-Side Synchronous Rectifier Driver

Part	Current - Supply	Applications	Package / Case	Mounting Type	Voltage - Supply [Max]	Voltage - Supply [Min]	Operating Temperature [Max]	Operating Temperature [Min]
Analog Devices LT8309HS5#TRMPBF	300 µA	Secondary-Side Controller	SOT-23-5 Thin TSOT-23-5	Surface Mount	40 VDC	4.5 V
Analog Devices LT8309IS5#TRPBF	300 µA	Secondary-Side Controller	SOT-23-5 Thin TSOT-23-5	Surface Mount	40 VDC	4.5 V	125 °C	-40 °C

Catalog

Secondary-Side Synchronous Rectifier Driver

Key Features

• Works with DCM and BCM/CrCM Conduction Mode Flyback Topologies

• VCC: 4.5V to 40V

• Supports Up to 150V MOSFETs

• 26ns Turn-Off Propagation Delay

• Accurate Minimum On and Off Timers for Reliable Operation

• Adjustable and Accurate Trip Point: +5mV to –30mV

• 1Ω Gate Driver Pull-Down

• SOT-23 5-Lead Package

Description

The LT8309 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.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 VCCrating allows the part to be driven from the output voltage or the rectified drain voltage of the MOSFET. A low quiescent current of 400μA maximizes efficiency at low output currents.ApplicationsHigh Output Current FlybacksHigh Efficiency Flybacks