XRP7725 Datasheet, PDF (32/34 Pages) Exar Corporation – Power Management System

XRP7725
Intel Node Manager Compatible Programmable
Power Management System
XRP7725. A diode in series with a resistor
between the LDO5 and ENABLE pins may
offer a way to more quickly pull down the
LDO5 output when the ENABLE pin is pulled
low.
APPLICATION INFORMATION
THERMAL DESIGN
As a four channel controller with internal
MOSFET drivers and 5V gate drive supply all
in one 7x7mm 44pin TQFN package, there is
the potential for the power dissipation to
exceed the package thermal limitations. The
XRP7725 has an internal LDO which supplies
5V to the internal circuitry and MOSFET
drivers during startup. It is generally
expected that either one of the switching
regulator outputs is 5V or another 5V rail is
available in the system and connected to the
5 Volt EXT pin. If there is no 5V available in
the system, then the power loss will increase
significantly and proper thermal design
becomes critical. For lower power levels
using properly sized MOSFETs, the use of the
internal 5V regulator as a gate drive supply is
considered appropriate.
LAYOUT GUIDELINES
Refer to application note ANP-32 “Practical
Layout Guidelines for Power^XR Designs and
ANP-35 “XRP77XX: Extending the MOSFET
Gate Drive Conductors”.
© 2014 Exar Corporation
32/34
Rev. 1.0.0