VSC8201 Datasheet, PDF (2/21 Pages) Vitesse Semiconductor Corporation – Single Port 10/100/1000BASE-Tand 1000BASE-X PHY

VSC8201DL
Table 2: Power Supply Decoupling for separate 3.3v and 1.5v Power Supplies
PCB Power Plane
Bulk Decoupling required
Local Decoupling Required
V+IO
V+A33
1 pair of 22uF, 1uF
1 pair of 22uF, 1uF and 1 10uF
Four 0.1uF capacitors
Two 0.1 uF capacitors
V+A15
V+DIG
1 pair of 2.2uF, 1uF
1 pair of 22uF, 1uF
One 0.1 uF capacitor
Four 0.1uF capacitors
Table 3: Power Supply Decoupling for single 3.3v Supply and Optional fixed 1.5v Regulator
PCB Power Plane
Bulk Decoupling required
Local Decoupling Required
V+IO
1 pair of 22uF, 1uF
Four 0.1uF capacitors
V+A33
V+A15
V+DIG
1 pair of 22uF, 1uF and 1 10 uF
1 pair of 2.2uF, 1uF
2.2uF
Two 0.1uF capacitors
One 0.1 uF capacitor
Four 0.1uF capacitors
The following figure shows the proposed layout for the local decoupling capacitors. The figure is approximately drawn to scale for stan-
dard 0603 size capacitors. Vias to the power and ground planes immediately in the vicinity of the capacitors provide a low inductive path
and aid in heat dissipation.
103
64
104
63
105
62
106
61
107
60
108
59
109
58
110
57
111
56
112
113
VSC8201
55
54
114
53
115
52
116
51
117
50
118
128 LQFP
49
119
120
(Top View)
48
47
121
46
122
45
123
44
124
43
125
42
126
41
127
40
128
39
Note:Place vias close to or under neath the capacitor pads for
low inductive path and higher heat dissipation rate.
0.1 uF
Figure 1: Local High-Frequency decoupling Capacitor Layout - LQFP package
Rev. 1.6.3 - 9/29/04
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