Intel 820E manual Dual-Footprint Analog Interface

Intel® 820E Chipset

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Figure 77. Dual-Footprint Analog Interface

Intel® 82562EH/82562ET
TDP		Tip		Intel
		Ring	RJ11	82562EH
TDN				config.
	Magnetics
RDP	module	TXP		Intel
RDN		TXN	RJ45	82562ET
				config.
		IO_subsys_dual_footprint_analog_
		IF

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 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.

•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.

Design Guide 121