Texas Instruments AM1808 User Manual page 131

www.ti.com
6.14.2.3 PCB Stackup Specifications
Table 6-44 shows the stackup and feature sizes required for SATA.
PCB Routing/Plane Layers
Signal Routing Layers
Number of ground plane cuts allowed within SATA routing region
Number of layers between SATA routing region and reference ground plane
PCB Routing Feature Size
PCB Trace Width w
PCB BGA escape via pad size
PCB BGA escape via hole size
Device BGA pad size
(1) Please refer to the Flip Chip Ball Grid Array Package Reference Guide (SPRU811) for device BGA pad size.
6.14.2.4 Routing Specifications
The SATA data signal traces are edge-coupled and must be routed to achieve exactly 100 Ohms
differential impedance. This is impacted by trace width, trace spacing, distance between planes, and
dielectric material. Verify with a proper PCB manufacturing tool that the trace geometry for both data
signal pairs results in exactly 100 ohms differential impedance traces.
specifications for the data and REFCLK signals.
Device to SATA header trace length
REFCLK trace length from oscillator to Device
Number of stubs allowed on SATA traces
TX/RX pair differential impedance
Number of vias on each SATA trace
SATA differential pair to any other trace spacing
(1) The SATA_REFCLK(P/N) pins include an internal 100 Ohms differential termination
(2) Vias must be used in pairs with their distance minimized.
(3) DS is the differential spacing of the SATA traces.
6.14.2.5 Coupling Capacitors
AC coupling capacitors are required on the receive data pair as well as the REFCLK pair.
shows the requirements for these capacitors.
Table 6-46. SATA Bypass and Coupling Capacitors Requirements
SATA AC coupling capacitor value
SATA AC coupling capacitor package size
(1) LxW, 10 mil units, i.e., a 0402 is a 40x20 mil surface mount capacitor.
(2) The physical size of the capacitor should be as small as possible.
Copyright © 2010–2014, Texas Instruments Incorporated
Table 6-44. SATA PCB Stackup Specifications
PARAMETER
(1)
Table 6-45. SATA Routing Specifications
PARAMETER
(1)
PARAMETER
Submit Documentation Feedback
Product Folder Links:
SPRS653E – FEBRUARY 2010 – REVISED MARCH 2014
MIN TYP
4 6
2 3
4
4
18
8
Table 6-45
MIN TYP
100
(3)
2*DS
MIN TYP
0.3 10
Peripheral Information and Electrical Specifications
AM1808
AM1808
MAX UNIT
Layers
Layers
0 Layers
0
Mils
Mils
Mils
Mils
shows the routing
MAX UNIT
7000 Mils
2000 Mils
0 Stubs
Ohms
(2)
3 Vias
Table 6-46
MAX UNIT
12 nF
(1) (2)
0603 10 Mils
131