Intel 820E Benutzerhandbuch
Intel
®
820E Chipset
R
Design Guide
121
Figure 77. Dual-Footprint Analog Interface
IO_subsys_dual_footprint_analog_
IF
IF
Magnetics
module
TDP
RJ45
Intel
®
82562EH/82562ET
TDN
RDP
RDN
RJ11
TXP
TXN
Tip
Ring
Intel
82562EH
82562EH
config.
Intel
82562ET
82562ET
config.
Additional guidelines for this configuration are as follows:
•
L = 0.5 inch to 6.5 inches
•
Stub = <0.5 inch
•
Either the Intel
82562EH or Intel
82562ET/82562EM component can be installed. Not both.
•
Pins 28, 29, and 30 of the Intel
82562ET component overlap pins 17, 18, and 19 of the Intel
82562EH component.
•
Overlapping pins are tied to ground.
•
No other signal pads should overlap or touch.
•
Signal lines LAN_CLK, LAN_RSTSYNC, LAN_RXD[0], LAN_TXD[0], RDP, RDN, RXP/Ring,
and RXN/Tip are shared by the Intel
and RXN/Tip are shared by the Intel
82562EH and Intel
82562ET component configurations.
•
No stubs should be present when the Intel
82562ET component is installed.
•
The packages used for the dual footprint are the TQFP for the Intel
82562EH component and the
SSOP for the Intel
82562ET component.
•
A 22
Ω
resistor can be placed at the driving side of the signal line to improve signal quality on the
LAN connect interface.
•
Resistors should be placed as close as possible to components.
•
Use components that can satisfy both the Intel
82562ET and Intel
82562EH component
configurations (i.e., a magnetics module).
•
Install components for either the Intel
82562ET or Intel
82562EH component configuration. Only
one configuration can be installed at a time.
•
Route shared signal lines such that stubs are not present or are minimized.
•
Stubs may occur on shared signal lines (i.e., RDP and RDN). These stubs result from traces routed
to an uninstalled component.
to an uninstalled component.
•
Use 0
Ω
resistors to connect and disconnect circuitry not shared by both configurations. Place
resistor pads along the signal line to reduce stub lengths.
•
Refer to the Intel 820E CRB layout for routing examples.