June 2008 Rev 1 1/16
1
L6743B
High current MOSFET driver
Features
■ Dual MOSFET driver for synchronous rectified
converters
■ High driving current for fast external MOSFET
switching
■ Integrated bootstrap diode
■ High frequency operation
■ Enable pin
■ Adaptive dead-time management
■ Flexible gate-drive: 5 V to 12 V compatible
■ High-impedance (HiZ) management for output
stage shutdown
■ Preliminary OV protection
■ VFDFPN8 3 x 3 mm package
Applications
■ High current VRM / VRD for desktop / server /
workstation CPUs
■ High current and high efficiency DC / DC
converters
Description
L6743B is a flexible, high-frequency dual-driver
specifically designed to drive N-channel
MOSFETs connected in synchronous-rectified
buck topology.
Combined with ST PWM controllers, the driver
allows implementing complete voltage regulator
solutions for modern high-current CPUs and
DC-DC conversion in general. L6743B embeds
high-current drivers for both high-side and
low-side MOSFETs. The device accepts flexible
power supply (5 V to 12 V) to optimize the
gate-drive voltage for high-side and low-side
maximizing the system efficiency.
The bootstrap diode is embedded saving the use
of external diodes. Anti shoot-through
management avoids high-side and low-side
MOSFET to conduct simultaneously and,
combined with adaptive dead-time control,
minimizes the LS body diode conduction time.
L6743B embeds preliminary OV protection: after
Vcc overcomes the UVLO and while the device is
in HiZ, the LS MOSFET is turned ON to protect
the load in case the output voltage overcomes a
warning threshold protecting the output against
HS failures.
The driver is available is VFDFPN8 3 x 3 mm
packages.
VFDFPN8 3 x 3 mm
Table 1. Device summary
Order code Package Packing
L6743B
VFDFPN8
Tube
L6743BTR Tape and reel
www.st.com
