USB 3.0 Hub Design Guide
© 2015 Genesys Logic, Inc. - All rights reserved.
Page 16
GLI Confidential
2.5
Power Source
Make sure that the DC to DC converter output voltage is 1.2V. Follow the PCB layout guidelines for optimal
performance of UP1722PDE6.
1.
For the main current paths, keep their traces short, direct and wide.
2.
Put the input/output capacitors as close as possible to the device pins.
3.
LX node is with high frequency voltage swing and should be kept in small area. Keep analog components
away from LX node to prevent stray capacitive noise pick-up.
4.
Keep the connect feedback network behind the output capacitors. Place the feedback components near the
UP1722PDE6 and keep the loop area small. .
5.
A ground plane is preferred, but if not available, keep the signal and power grounds segregated with small
signal components returning to the GND pin at one point. They should not share the high current path of
C
IN
or C
OUT
.
6.
Flood all unused areas on all layers with copper. Flooding with copper will reduce the temperature rise of
power components. These copper areas should be connected to VIN or GND.
Figure 2.14