LT8309HS5#TRMPBF

LT8309HS5#TRMPBF 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 behaviour 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 0.8ohm 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 quiescent current of 400µA maximizes efficiency at low output currents. Applications include high output current flybacks, high efficiency flybacks.

• Accurate minimum on and off timers for reliable operation
• 1ohm gate driver pull-down
• Input voltage range from 4.5 to 40V
• VCC quiescent current is 300µA typ at not switching, INTVCC = 8V
• Drain current is 10µA typical (out of pin)
• Dropout (VCC to INTVCC) is 1.3V at IINTVCC = –10mA, VIN = 7V
• Turn-on propagation delay (tD(ON)) is 31ns typ at RS = 0 ohm, –100mVOD, VDS to VGATE
• Turn-off propagation delay (tD(OFF)) is 26s typ at RS = 0 ohm, –100mVOD, VDS to VGATE
• 5-lead plastic TSOT-23 package
• Temperature range from -40°C to +150°C

Notes

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