Dimm Solution With FET Switches, Registered Sdram

Design Checklist

3.6.2DIMM Solution With FET Switches

•With existing 64Mbit technology, 512 MB, 1 GB and 2 GB support for servers and workstations must have 4 double sided DIMMs.

•500 ohm - 1K ohm pull-down resistors on each of the second inputs (1A2, 2A2, etc.) are recommended on the FET switches (500 ohms is recommended based on simulation) to prevent a direct short to ground while switching.

Figure 3-3. Current Solution With Existing FET Switches

				D	D
	DQ 0 - 71	F E T	DQA 0 - 71	I	I
		F E T		I	I
		S W	DQB 0 - 71	M	M
8 2 4 4 3 G X			DQB 0 - 71	M	M
8 2 4 4 3 G X				M	M
				0	4
R 0	R 7 1	FENA
					v009.vsd

•All 72 DQ lines are fed through the FET switch.

•The current FET switch is Pericom PI5C16212A, package type A56. See third-party vendor list for more FET switch vendors.

•12 functional units per part requires 6 devices on motherboard.

3.6.3Registered SDRAM

•There may be power and thermal considerations for registered DIMMs. If a design is going to support registered DIMMs, the DIMM spacing may need to be evaluated based on mechanical and cooling issues.

•REGE, pin 147 on all the DIMMs needs a 0 ohm pull-up to enable registered DIMMs.

•Data lines are directly connected to the SDRAM components, while all address and control signals are registered. The clock signal is routed via a PLL to all the SDRAM devices.

•Access to registered DIMMs requires an additional clock of leadoff latency, programmable in the 82443GX.

Intel®440GX AGPset Design Guide

3-15

440GX specifications

The Intel 440GX chipset was launched in 1997 as part of Intel's series of chipsets known as the 440 family, and it served as a critical component for various Pentium II and Pentium III-based motherboard architectures. Specifically designed for the second generation of Intel’s processors, the 440GX delivered enhanced performance and supported a range of important technologies that defined PC architectures of its time.

One of the main features of the Intel 440GX was its support for a 100 MHz front-side bus (FSB), which significantly improved data transfer rates between the CPU and the memory subsystem. This advancement allowed the 440GX to accommodate both the original Pentium II processors as well as the later Pentium III chips, providing compatibility and flexibility for system builders and consumers alike.

The 440GX chipset included an integrated AGP (Accelerated Graphics Port) controller, which supported AGP 2x speeds. This enabled high-performance graphics cards to be utilized effectively, delivering many enhanced graphics capabilities for gaming and multimedia applications. The AGP interface was crucial at the time as it offered a dedicated pathway for graphics data, increasing bandwidth compared to traditional PCI slots.

In terms of memory support, the 440GX could address up to 512 MB of SDRAM, allowing systems built with this chipset to run comfortably with sufficient memory for the era’s demanding applications. The memory controller was capable of supporting both single and double-sided DIMMs, which provided versatility in memory configuration for system builders.

Another notable feature of the Intel 440GX was its support for multi-processor configurations through its Dual Processors support feature. This allowed enterprise and workstation computers to leverage the performance advantages of multiple CPUs, making the chipset suitable for business and professional environments where multitasking and high-performance computing were essential.

On the connectivity front, the chipset supported up to six PCI slots, enhancing peripheral device integration and expansion capabilities. It also included integrated IDE controllers, facilitating connections for hard drives and CD-ROM devices.

Overall, the Intel 440GX chipset represented a balanced combination of performance, flexibility, and technology advancements for its time. Its introduction helped establish a foundation for subsequent advancements in PC technology and set the stage for more powerful computing systems in the years to come.

Intel 440GX manual Dimm Solution With FET Switches, Registered Sdram

Models: 440GX