Description
The L6983I is a device specifically designed for isolated buck topology. The primary output voltage can be accurately adjusted, whereas the isolated secondary output is derived by using a given transformer ratio. No optocoupler is required. The primary sink capability up to -4.5 A (even during soft-start) allows a proper energy transfer to the secondary side as well as enabling a tracked soft-start of the secondary output. The control loop is based on a peak current mode architecture and the device operates in forced PWM. The 390 ns blanking time filters oscillations, generated by the transformer leakage inductance, making the solution more robust.
The compact QFN16 3x3 mm package and the internal compensation of the L6983I help minimize design complexity and size.

FEATUREs
• Designed for iso-buck topology
• 3.5 V to 38 V operating input voltage
• Primary output voltage regulation / no optocoupler required
• 4.5 A source / sink peak primary current capability
• Peak current mode architecture in forced PWM operation
• 390 ns blanking time
• 200 kHz to 1 MHz programmable switching frequency. Stable with low ESR capacitor: min 2 µF
• Internal compensation network
• 2 μA shutdown current
• Internal soft-start
• Enable
• Overvoltage protection
• Output voltage sequencing
• Thermal protection
• Optional spread spectrum for improved EMC
• Power Good
• Synchronization to external clock
• QFN16 (3x3 mm) package

APPLICATIONs
• Isolated IGBT/SiC MOSFET gate drive supply
• OBC (On-board charger) for HEV/EV
• Electric traction systems