USB 3.0 Hub Design Guide
© 2015 Genesys Logic, Inc. - All rights reserved.
Page 20
GLI Confidential
2.10
GL3521 Layout Notice
1.
The layout trace diagram of 1.2V power is described as
Fig. 2.20
. The width of SW 1.2V power trace line is
recommended to be 40 mils. The trace of FB is recommended to be as short as possible, and not to be routed
through the layer of EMI protection. Please also refer to Section 3.4 Power Source for more information.
The resistor divider R1 and R2 must be connected between the (+) plate of C
OUT
and a ground line
terminated near GND. The SW should be connected to inductor by wide and short trace, and keep sensitive
components away from this trace. There is large current passing though the pin 88 GND of GL3521. This
pin has to be connected with the ground of C
IN
and C
OUT
, and the trace has to be wide. Increase the amount
of via holes at the ground of pin 88. Increase via holes at the ground of C
IN
and C
OUT
2.
The layout trace diagram of 1.2V or 3.3V power trace is described as
Fig. 2.21
. The width of DVDD12
power trace line is recommended to be 40 mils, and the width of DVDD33 power trace line is to be 30 mils.
3.
Please reduce at least 2 vias when the 5V or 12V power trace is needed to go through different layers. Please
refer to the
Fig. 2.22
for more detailed information.
Figure 2.20
Figure 2.21