1CYM74S550,
CYM74S551
CYM74B550
CYM74P550A
CYM74S550, CYM74S551
PRELIMINARY
OPTi Viper Chip Set Level II
Cache Module Family
volt SRAMs and 3.3 volt level translators. These modules offer
3-2-2-2 performance at CPU bus speeds up to 66 MHz.
Features
• Pin-compatible secondary cache module family
The synchronousmodules are available with low cost synchro-
nous pipelined RAMs or high performance synchronous burst
RAMs.
• Asynchronous (CYM74B550), synchronous pipelined
(CYM74P550A), or synchronous burst (CYM74S550,
CYM74S551) modules
The CYM74P550A is a high performance synchronous pipe-
lined burst 256 KB module and is based on industry standard
32Kx32 pipelined BSRAM. The CYM74P550A has series
damping resistors on the data lines.
• Ideal for Intel P54C/P55C systems with the OPTi Viper
chipset
• Operates at 50, 60, and 66 MHz
• Uses cost-effective CMOS asynchronous SRAMs or
high-performance synchronous SRAMs
• 160-position Burndy DIMM CELP2X80SC3Z48 connec-
tor
The CYM74S550 and CYM74S551 are high performance syn-
chronous burst cache modules that provide 256-Kbytes and
512-Kbytes of cache respectively. These modules support
3-1-1-1 performance at 66 MHz.
• 3.3V inputs/ data outputs
All of these modules include storage for 8-bits of tag and one
dirty bit. Multiple ground pins and on-board decoupling capac-
itors ensure high performance with maximum noise immunity.
Functional Description
This family of secondary cache modules is designed for Intel
P54C/P55C systems with the OPTi Viper chip set.
All components on the cache modules are surface mounted on
a multi-layer epoxy laminate (FR-4) substrate. The contact
pins are plated with 100 micro-inches of nickel covered by 10
micro-inches of gold flash.
CYM74B550 is a low cost asynchronous cache module that
provides 256-Kbytes of cache with industry standard 32Kx8 5
Logic Block Diagram
-
CYM74B550
PD
PD
NC
PD
PD
0
3
2
1
TAGWE
CYM74B550 NC
GND GND
16Kx1
WE
8Kx8
DIRTYWE
DIRTYI
WE
D
D
A
Q
TAG –TAG
7
0
A
13:0
13:0
–A
5
A
17
–A
A
17
5
A
17
–A
5
2X
373C
DIRTYO
LA –LA
17
5
32Kx 8
5V only SRAMs
HACALE
LE
LA
A
–LA
17
14:2
5
CD –CD
D
63
0
A
1
OCA
ECA
4
4
A
0
WE
OE
CE
ECAWE
ECDOE
CE
CS
CE
CS
CE
CE
CS
CE
CS
CE
CS
CE
CS
LSB
0
CS
CS
4
7
6
5
3
2
1
CS –CS
7
0
100 ohms
V
CC
V
CC5
4.3V zener
5% tolerance
7X
CYBUS3384
GND
D
–D
A
B
CD –CD
63
0
63
0
module 3.3V compliant databus
BE
2
1
GND
BE
74b550-1
Intel is a trademark of Intel Corporation.
OPTi is a trademark of OPTi, Inc.
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134
July 1995 - Revised October 1996
•
408-943-2600
