LM2722 High Speed Synchronous/Asynchronous MOSFET Driver
December 2001
LM2722
High Speed Synchronous/Asynchronous MOSFET Driver
General Description
The LM2722, part of the LM2726 family, is designed to be
used with multi-phase controllers. This part differs from the
LM2726 by changing the functionality of the SYNC_EN pin
from a whole chip enable to a low side MOSFET enable. As
a result, the SYNC_EN pin now provides control between
Synchronous and Asynchronous operations. Having this
control can be advantageous in portable systems since
Asynchronous operations can be more efficient at very light
loads.
The LM2722 drives both top and bottom MOSFETs in a
push-pull structure simultaneously. It takes a logic level
PWM input and splits it into two complimentary signals with
a typical 20ns dead time in between. The built-in
cross-conduction protection circuitry prevents the top and
bottom FETs from turning on simultaneously. The
cross-conduction protection circuitry detects both the driver
outputs and will not turn on a driver until the other driver
output is low. With a bias voltage of 5V, the peak sourcing
and sinking current for each driver of the LM2722 is typically
3A. In an SO-8 package, each driver is able to handle 50mA
average current. Input UVLO (Under-Voltage-Lock-Out)
forces both driver outputs low to ensure proper power-up
and power-down operation. The gate drive bias voltage
needed by the high side MOSFET is obtained through an
external bootstrap. Minimum pulse width is as low as 55ns.
Features
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Synchronous or Asynchronous Operation
Adaptive shoot-through protection
Input Under-Voltage-Lock-Out
Typical 20ns internal delay
Plastic 8-pin SO package
Applications
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Driver for LM2723 Intel Mobile Northwood CPU core
power supply.
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High Current DC/DC Power Supplies
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High Input Voltage Switching Regulators
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Fast Transient Microprocessors
Typical Application
20028901
Note: National is an Intel Mobile Voltage Positioning (IMVP) licensee.
漏 2001 National Semiconductor Corporation
DS200289
www.national.com
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