Texas Instruments DS90UB926QSEVB, User Manual

Page: 17 / 35

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Sept 2012 Literature Number: SNLU114 17
6. Appendix – Use of optional mini-B USB connector (J2)
Use this option when connecting to standard DS90UR905Q EVB.
Populate R69 and R70 with 0201 sized 0
Ω
resistor (suggest Panasonic ERJ-1GE0R00C or
equivalent). R69 and R70 pads are on the back side of the EVM under J1. This will connect
J2. Ideally, J1 (Rosenberger HSD connector) should be removed to eliminate the stub.
Warning: R68 and R71 should not be populated when using J2.
RE
D
RIN-_USB
VIA2
CON1
1
BLK
J2
mini USB 5pin_open
1
2
3
4
5
6 78
9
VIA1
CON1
1
VSS
VSS
JP8
3-Pin Header_open
1 2 3
VSS
RIN-
JP9
3-Pin Header_open
1 2 3
RIN+
R69
0 ohm_open
0201
R70
0 ohm_open
0201
mini B:
component side
(TOP)
RIN+_USB
Add a two pin jumper on JP8 and JP9; this will ground the unused wires in the USB cable.
7. Appendix - Board Layout
Figure 5, Figure 6, Figure 7, and Figure 8 show the board layout for the DS90UB926Q EVB.
The DS90UB926Q is a 4-layer board (TOP / GND / PWR / BOTTOM). The 50
Ω
microstrip trace on the top
layer of the board is referenced to GND, and the 100
Ω
differential traces are referenced to GND.