SigmaRAM Family Overview

The IS61NSCS series ΣRAMs are built in compliance with the SigmaRAM pinout standard for synchronous SRAMs. The implementations are 18,874,368-bit (18Mb) SRAMs. These are the first in a family of wide, very low voltage CMOS I/O SRAMs designed to operate at the speeds needed to implement economical high performance networking systems.

Features

? JEDEC SigmaRam pinout and package standard

? Single 1.8V power supply (VCC): 1.7V (min) to 1.9V (max)

? Dedicated output supply voltage (VCCQ): 1.8V or 1.5V typical

? LVCMOS-compatible I/O interface

? Common data I/O pins (DQs)

? Single Data Rate (SDR) data transfers

? Pipelined (PL) read operations

? Double Late Write (DLW) write operations

? Burst and non-burst read and write operations, selectable via dedicated control pin (ADV)

? Internally controlled Linear Burst address sequencing during burst operations

? Burst length of 2, 3, or 4, with automatic address wrap

? Full read/write coherency

? Byte write capability

? Two cycle deselect

? Single-ended input clock (CLK)

? Data-referenced output clocks (CQ/CQ)

? Selectable output driver impedance via dedicated control pin (ZQ)

? Echo clock outputs track data output drivers

? Depth expansion capability (2 or 4 banks) via programmable chip enables (E2, E3, EP2, EP3)

? JTAG boundary scan (subset of IEEE standard 1149.1)

? 209 pin (11x19), 1mm pitch, 14mm x 22mm Ball Grid Array (BGA) package