GS84118AT/B-166/150/130/100
TQFP, BGA
Commercial Temp
Industrial Temp
256K x 18 Sync
Cache Tag
166 MHz–100 MHz
3.3 V V
DD
3.3 V and 2.5 V I/O
Features
• 3.3 V +10%/–5% core power supply
• 2.5 V or 3.3 V I/O supply
• Intergrated data comparator for Tag RAM application
• FT mode pin for flow through or pipeline operation
• LBO pin for Linear or Interleave (Pentium
TM
and X86) Burst
mode
• Synchronous address, data I/O, and control inputs
• Synchronous Data Enable (DE)
• Asynchronous Output Enable (OE)
• Asynchronous Match Output Enable (MOE)
• Byte Write (BWE) and Global Write (GW) operation
• Three chip enable signals for easy depth expansion
• Internal self-timed write cycle
• JTAG Test mode conforms to IEEE standard 1149.1
• JEDEC-standard 100-lead TQFP and 119-BGA packages
• Pb-Free 100-lead TQFP package available
Functional Description
The GS84118A is a 256K x 18 high performance synchronous
SRAM with integrated Tag RAM comparator. A 2-bit burst
counter is included to provide burst interface with Pentium
TM
and other high performance CPUs. It is designed to be used as
a Cache Tag SRAM, as well as data SRAM. Addresses, data
IOs, match output, chip enables (CE1, CE2, CE3), address
control inputs (ADSP, ADSC, ADV), and write control inputs
(BW1, BW2, BWE, GW, DE) are synchronous and are
controlled by a positive-edge-triggered clock (CLK).
Output Enable (OE), Match Output Enable, and power down
control (ZZ) are asynchronous. Burst can be initiated with
either ADSP or ADSC inputs. Subsequent burst addresses are
generated internally and are controlled by ADV. The burst
sequence is either interleave order (Pentium
TM
or x86) or
linear order, and is controlled by LBO.
Output registers and the Match output register are provided and
controlled by the FT mode pin (Pin 14). Through use of the FT
mode pin, I/O registers can be programmed to perform pipeline
or flow through operation. Flow Through mode reduces
latency.
Byte write operation is performed by using Byte Write Enable
(BWE) input combined with two individual byte write signals
BW1-2. In addition, Global Write (GW) is available for
writing all bytes at one time.
Compare cycles begin as a read cycle with output disabled so
that compare data can be loaded into the data input register.
The comparator compares the read data with the registered
input data and a match signal is generated. The match output
can be either in Pipeline or Flow Through modes controlled by
the FT signal.
Low power (Standby mode) is attained through the assertion of
the ZZ signal, or by stopping the clock (CLK). Memory data is
retained during Standby mode.
JTAG boundary scan interface is provided using IEEE
standard 1149.1 protocol. Four pins—Test Data In (TDI), Test
Data Out (TDO), Test Clock (TCK) and Test Mode Select
(TMS)—are used to perform JTAG function.
The GS84118A operates on a 3.3 V power supply and all
inputs/outputs are 3.3 V or 2.5 V LVTTL-compatible.
Separate output (V
DDQ
) pins are used to allow both 3.3 V or
2.5 V IO interface.
* Pentium is a trademark of Intel Corp.
Parameter Synopsis
-166
Pipeline
3-1-1-1
Flow
Through
2-1-1-1
t
cycle
t
KQ
I
DD
t
KQ
t
cycle
I
DD
6.0 ns
3.5 ns
310 mA
8.5 ns
10 ns
190 mA
-150
6.6 ns
3.8 ns
275 mA
10 ns
10 ns
190 mA
-133
7.5 ns
4.0 ns
250 mA
11 ns
15 ns
140 mA
-100
10 ns
4.5 ns
190 mA
12 ns
15 ns
140 mA
Rev: 1.02 4/2005
1/20
© 2001, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
* Pentium is a trademark of Intel
GS84118AT/B-166/150/130/100
Pin Description
Symbol
An
CLK
BWE
BW1
BW2
GW
CE1,CE2, CE3
OE
ADV
ADSP, ADSC
DQ1–DQ16
DQP1–DQP2
MATCH
MOE
DE
ZZ
FT
LBO
TMS
TDI
TDO
TCK
V
DD
V
SS
V
DDQ
NC
Description
Address Input Signals
Clock Input Signal
Byte Write Enable Signal—The byte write enable signal needs to be combined with one of the four
byte write signals for a write operation to occur.
Byte Write signal for data outputs 1 thru 8
Byte Write signal for data outputs 9 thru 16
Global Write Enable
Chip Enables
Output Enable
Burst address advance
Address status signals
Data Input and Output pins
Parity Input and Output pins
Match Output
Match Output Enable
Data Enable—Data input registers are updated only when DE is active.
Power down control—Application of ZZ will result in a low standby power consumption.
Flow Through or Pipeline mode
Linear Order Burst mode
Test Mode Select
Test Data In
Test Data Out
Test Clock
3.3 V power supply
Ground
2.5 V/3.3 V output power supply
No Connect
Rev: 1.02 4/2005
4/20
© 2001, GSI Technology
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
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