XRP7720 Datasheet, PDF (26/28 Pages) Exar Corporation – Quad Output Universal Customizable PMIC with PFM

XRP7720
Quad Output Universal Customizable PMIC with PFM
APPLICATION INFORMATION
THERMAL DESIGN
As a 4 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
XRP7720 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
5VEXT 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 and 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”, as
well as ANP-35 for routing long distance gate
drive traces.
© 2014 Exar Corporation
26/28
Rev. 1.0.0