AM3359, AM3358, AM3357, AM3356, AM3354, AM3352
SPRS717H – OCTOBER 2011 – REVISED MAY 2015
Complete stackup specifications are provided in
Table 7-46. PCB Stackup Specifications
NO.
PARAMETER
MIN
TYP
MAX
UNIT
1
PCB routing and plane layers
4
2
Signal routing layers
2
3
Full ground layers under DDR2 routing region
1
4
Number of ground plane cuts allowed within DDR2 routing region
0
5
Full VDDS_DDR power reference layers under DDR2 routing region
1
6
Number of layers between DDR2 routing layer and reference ground plane
0
7
PCB routing feature size
4
mils
8
PCB trace width, w
4
mils
9
PCB BGA escape via pad size
18
20
mils
10
PCB BGA escape via hole size
10
mils
11
Single-ended impedance, Zo
50
75
Ω
12
Impedance control
Zo-5
Zo
Zo+5
Ω
(1) For the DDR2 device BGA pad size, see the DDR2 device manufacturer documentation.
(2) A 20-10 via may be used if enough power routing resources are available. An 18-10 via allows for more flexible power routing to the
AM335x device.
(3) Zo is the nominal singled-ended impedance selected for the PCB.
(4) This parameter specifies the AC characteristic impedance tolerance for each segment of a PCB signal trace relative to the chosen Zo
defined by the single-ended impedance parameter.
(5) Tighter impedance control is required to ensure flight time skew is minimal.
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