AB32

www.DataSheet4U.com 123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234567890123 123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789012123456789012345678901234567890121234567890123 12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789012123456789012 12345678901234567890123456789012123456789012345678901234567890121234567890123456789012345678901212345678901234567890123456789012123456789012 Application Brief AB-32 Application Brief AB32 3.3V Bus Switches for PC100 /PC133 DIMM Switching TM TM by Refugio Jones August 18, 1999 Highlights In high-end PC and server applications, the Pentium IITM processor memory bus runs at bus speeds of 100 or 133 MHz. Here, bus switches are used to switch 100/133 MHz SDRAM modules in densities of 128 MBytes and higher. Pericom’s 3.3V DIMM bus switch series is designed with near zero delay, low ON Resistance (five ohms), low-capacitance, and ultralow quiescent power. For reliability, the unused module data pins should be connected to ground. Figure 1 shows the application of Pericom’s PI3B16226 bus switches in a Intel Pentium II memory system with bus speeds of 133 MHz and 133 MHz SDRAM DIMMs. To prevent overloading, a bus switch is required where more than three SDRAM DIMMs are connected to the bus. The block diagram shows that the DIMM modules are co...