Rev: 1.01 3/2002
1/34
2001, Giga Semiconductor, Inc.
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
ByteSafe is a Trademark of Giga Semiconductor, Inc. (GSI Technology).
Preliminary
GS881E18/36AT-250/225/200/166/150/133
512K x 18, 256K x 36
9Mb Sync Burst SRAMs
250 MHz
133 MHz
2.5 V or 3.3 V V
DD
2.5 V or 3.3 V I/O
100-Pin TQFP
Commercial Temp
Industrial Temp
Features
FT pin for user-configurable flow through or pipeline opera-
tion
Dual Cycle Deselect (DCD) operation
IEEE 1149.1 JTAG-compatible Boundary Scan
2.5 V or 3.3 V +10%/10% core power supply
2.5 V or 3.3 V I/O supply
LBO pin for Linear or Interleaved Burst mode
Internal input resistors on mode pins allow floating mode pins
Default to Interleaved Pipeline mode
Byte Write (BW) and/or Global Write (GW) operation
Internal self-timed write cycle
Automatic power-down for portable applications
JEDEC-standard 100-lead TQFP package
Functional Description
Applications
The GS881E18/36AT is a 9,437,184-bit high performance
synchronous SRAM with a 2-bit burst address counter.
Although of a type originally developed for Level 2 Cache
applications supporting high performance CPUs, the device
now finds application in synchronous SRAM applications,
ranging from DSP main store to networking chip set support.
Controls
Addresses, data I/Os, chip enable (E1), address burst control
inputs (ADSP, ADSC, ADV) and write control inputs (Bx,
BW, GW) are synchronous and are controlled by a positive-
edge-triggered clock input (CK). Output enable (G) and power
down control (ZZ) are asynchronous inputs. Burst cycles can
be initiated with either ADSP or ADSC inputs. In Burst mode,
subsequent burst addresses are generated internally and are
controlled by ADV. The burst address counter may be
configured to count in either linear or interleave order with the
Linear Burst Order (LBO) input. The Burst function need not
be used. New addresses can be loaded on every cycle with no
degradation of chip performance.
Flow Through/Pipeline Reads
The function of the Data Output register can be controlled by
the user via the FT mode pin (Pin 14). Holding the FT mode
pin low places the RAM in Flow Through mode, causing
output data to bypass the Data Output Register. Holding FT
high places the RAM in Pipeline mode, activating the rising-
edge-triggered Data Output Register.
DCD Pipelined Reads
The GS881E18/36AT is a DCD (Dual Cycle Deselect)
pipelined synchronous SRAM. SCD (Single Cycle Deselect)
versions are also available. DCD SRAMs pipeline disable
commands to the same degree as read commands. DCD RAMs
hold the deselect command for one full cycle and then begin
turning off their outputs just after the second rising edge of
clock.
Byte Write and Global Write
Byte write operation is performed by using Byte Write enable
(BW) input combined with one or more individual byte write
signals (Bx). In addition, Global Write (GW) is available for
writing all bytes at one time, regardless of the Byte Write
control inputs.
Sleep Mode
Low power (Sleep mode) is attained through the assertion
(High) of the ZZ signal, or by stopping the clock (CK).
Memory data is retained during Sleep mode.
Core and Interface Voltages
The GS881E18/36AT operates on a 2.5 V or 3.3 V power
supply. All input are 3.3 V and 2.5 V compatible. Separate
output power (V
DDQ
) pins are used to decouple output noise
from the internal circuits and are 3.3 V and 2.5 V compatible.
-250 -225 -200 -166 -150 -133 Unit
Pipeline
3-1-1-1
t
KQ
tCycle
2.5
4.0
2.7
4.4
3.0
5.0
3.4
6.0
3.8
6.7
4.0
7.5
ns
ns
3.3 V
Curr (x18)
Curr (x36)
280
330
255
300
230
270
200
230
185
215
165
190
mA
mA
2.5 V
Curr (x18)
Curr (x36)
275
320
250
295
230
265
195
225
180
210
165
185
mA
mA
Flow
Through
2-1-1-1
t
KQ
tCycle
5.5
5.5
6.0
6.0
6.5
6.5
7.0
7.0
7.5
7.5
8.5
8.5
ns
ns
3.3 V
Curr (x18)
Curr (x36)
175
200
165
190
160
180
150
170
145
165
135
150
mA
mA
2.5 V
Curr (x18)
Curr (x36)
175
200
165
190
160
180
150
170
145
165
135
150
mA
mA
Rev: 1.01 3/2002
4/34
2001, Giga Semiconductor, Inc.
Specifications cited are subject to change without notice. For latest documentation see http://www.gsitechnology.com.
Preliminary
GS881E18/36AT-250/225/200/166/150/133
TQFP Pin Description
Pin Location
Symbol
Type
Description
37, 36
A
0
, A
1
I
Address field LSBs and Address Counter preset Inputs
35, 34, 33, 32, 100, 99, 82, 81, 44, 45, 46,
47, 48, 49, 50,
A
2
A
17
I
Address Inputs
80
A
18
I
Address Inputs (x18 versions)
63, 62, 59, 58, 57, 56, 53, 52, 51
68, 69, 72, 73, 74, 75, 78, 79, 80
13, 12, 9, 8, 7, 6, 3, 2, 1
18, 19, 22, 23, 24, 25, 28, 29, 30
DQ
A1
DQ
A9
DQ
B1
DQ
B9
DQ
C1
DQ
C9
DQ
D1
DQ
D9
I/O
Data Input and Output pins (x36 Version)
58, 59, 62, 63, 68, 69, 72, 73, 74
8, 9, 12, 13, 18, 19, 22, 23, 24
DQ
A1
DQ
A9
DQ
B1
DQ
B9
I/O
Data Input and Output pins (x18 Version)
51, 52, 53, 56, 57
75, 78, 79,
1, 2, 3, 6, 7,
25, 28, 29, 30, 95, 96, 97
NC
--
No Connect (x18 Version)
16, 66
NC
--
No Connect
87
BW
I
Byte Write
--
Writes all enabled bytes; active low
93, 94
B
A
, B
B
I
Byte Write Enable for DQ
A
, DQ
B
Data I/Os; active low
95, 96
B
C
, B
D
I
Byte Write Enable for DQ
C
, DQ
D
Data I/'s; active low
(x36 Version)
97
NC
--
No Connect (x36 Version)
89
CK
I
Clock Input Signal; active high
88
GW
I
Global Write Enable
--
Writes all bytes; active low
97
E
2
I
Chip Enable; active high
98
E
1
I
Chip Enable; active low
86
G
I
Output Enable; active low
83
ADV
I
Burst address counter advance enable; active low
84, 85
ADSP, ADSC
I
Address Strobe (Processor, Cache Controller); active low
64
ZZ
I
Sleep Mode control; active high
31
LBO
I
Linear Burst Order mode; active low
15, 41, 65, 91
V
DD
I
Core power supply
5, 10, 17, 21, 26, 40, 55, 60, 67, 71, 76, 90
V
SS
I
I/O and Core Ground
4, 11, 20, 27, 54, 61, 70, 77
V
DDQ
I
Output driver power supply
PDF 
ZIP
