S/UNI®-ATLAS-3200 Telecom Standard Product Data Sheet
Preliminary
5.2
RAM Configurations
The S/UNI-ATLAS-3200 device uses an external SRAM to store the search tree data structure.
This SRAM is required to be Synchronous Pipelined ZBT SRAM with cycle time less than 7 ns,
and a bus width of 64 bits + parity. The typical configuration is 8M of SRAM in a pair of
128Kx36 RAMs. This configuration will support 64K VCs. Up to 16M of SRAM may be used if
additional search depth is desired, though no more than 64K VCs are supported. Alternatively,
the amount of SRAM may be reduced, if less than 64K VCs are to be supported.
Figure 2 Interface between S/UNI-ATLAS-3200 and External RAM
128 K x 36
Pipelined ZBT
SRAM
128 K x 36
Pipelined ZBT
SRAM
Clock
Source
125 MHz
SDAT[31:0]
SPAR[3:0]
XCLK
S/UNI-ATLAS-3200
Proprietary and Confidential to PMC-Sierra, Inc., and for its Customers’ Internal Use
Document ID: PMC-1990553, Issue 4
33
PMC [ PMC-SIERRA, INC ]
