Intel 440GX manual Board Description, Motherboard Layout and Routing Guidelines, NLX Form Factor

Motherboard Layout and Routing Guidelines

NLX Form Factor:

1.The NLX placement and layout below is recommended for a single (UP) Intel® Pentium® II processor / Intel® 440GX AGPset system design.

2.The example placement below shows one Slot 1 connector, 4 DIMM sockets, and an AGP compliant device down.

3.For an NLX form factor design, the AGP compliant graphics device may readily be integrated on the motherboard (device down option).

4.The trace length limitation between critical connections will be addressed later in this document.

5.Figure 2-3is for reference only and the trade-off between the number of DIMM sockets, and other motherboard peripherals need to be evaluated for each design.

Figure 2-3. Example NLX Placement for a UP Intel® Pentium® II processor / Intel® 440GX Design

SDRAM DIMMs
			CK100	AGP
	SDRAM
	Interface		AGP Interface
CKBF	82443GX		PCI Interface
Host Interface
	Pentium ®	II Slot 1		Ports
				I/O
				PIIX4E
				PCI0/ISA Riser
				v003

2.2Board Description

For a single processor / Intel® 440GX AGPset motherboard design, a 4 layer stack-up arrangement is recommended. The stack up of the board is shown in Figure 2-4. The impedance of all the signal layers are to be between 50 and 80 ohms. Lower trace impedance will reduce signal edge rates, over & undershoot, and have less cross-talk than higher trace impedance. Higher trace impedance will increase edge rates and may slightly decrease signal flight times.

Intel®440GX AGPset Design Guide 2-3