The attached data sheets are prepared and approved by SAMSUNG Electronics. SAMSUNG Electronics CO., LTD. reserve the right to change the
specifications. SAMSUNG Electronics will evaluate and reply to your requests and questions on the parameters of this device. If you have any questions,
please contact the SAMSUNG branch office near your office, call or contact Headquarters.
-1-
December 1998
Rev 3.0
KM718V787A
128Kx18-Bit Synchronous Burst SRAM
FEATURES
• Synchronous Operation.
• On-Chip Address Counter.
• Write Self-Timed Cycle.
• On-Chip Address and Control Registers.
• V
DD
= 3.3V+0.3V/-0.165V Power Supply.
• V
DDQ
Supply Voltage 3.3V+0.3V/-0.165V for 3.3V I/O
or 2.5V+0.4V/-0.125V for 2.5V I/O.
• 5V Tolerant Inputs except I/O Pins.
• Byte Writable Function.
• Global Write Enable Controls a full bus-width write.
• Power Down State via ZZ Signal.
• Asynchronous Output Enable Control.
• ADSP, ADSC, ADV Burst Control Pins.
• LBO Pin allows a choice of either a interleaved burst or a linear
burst.
• Three Chip Enables for simple depth expansion with No Data
Contention.
• TTL-Level Three-State Output.
• 100-TQFP-1420A
128Kx18 Synchronous SRAM
GENERAL DESCRIPTION
The KM718V787A is 2,359,296 bits Synchronous Static Ran-
dom Access Memory designed to support zero wait state per-
formance for advanced Pentium/Power PC based system. And
with CS
1
high, ADSP is blocked to control signals.
It can be organized as 128K words of 18 bits. And it integrates
address and control registers, a 2-bit burst address counter and
high output drive circuitry onto a single integrated circuit for
reduced components counts implementation of high perfor-
mance cache RAM applications.
Write cycles are internally self-timed and synchronous.
The self-timed write feature eliminates complex off chip write
pulse shaping logic, simplifying the cache design and further
reducing the component count.
Burst cycle can be initiated with either the address status pro-
cessor(ADSP) or address status cache controller(ADSC)
inputs. Subsequent burst addresses are generated internally in
the system′s burst sequence and are controlled by the burst
address advance(ADV) input.
ZZ pin controls Power Down State and reduces Stand-by cur-
rent regardless of CLK.
The KM718V787A is implemented with SAMSUNG′s high per-
formance CMOS technology and is available in a 100pin TQFP
package. Multiple power and ground pins are utilized to mini-
mize ground bounce.
FAST ACCESS TIMES
PARAMETER
Cycle Time
Clock Access Time
Output Enable Access Time
Symbol
t
CYC
t
CD
t
OE
-7
8.5
7.5
3.5
-8
10
8
3.5
-9
12
9
3.5
Unit
ns
ns
ns
LOGIC BLOCK DIAGRAM
CLK
LBO
ADV
ADSC
BURST CONTROL
LOGIC
BURST
ADDRESS
COUNTER
A'
0
~
A'
1
REGISTER
128Kx18
MEMORY
ARRAY
CONTROL
A
0
~
A
1
ADDRESS
REGISTER
A
2
~
A
16
ADSP
A
0
~
A
16
DATA-IN
REGISTER
CS
1
CS
2
CS
2
GW
BW
WEa
WEb
REGISTER
CONTROL
CONTROL
LOGIC
OUTPUT
BUFFER
OE
ZZ
DQa
0
~ DQb
7
DQPa, DQPb
-2-
December 1998
Rev 3.0
KM718V787A
PIN CONFIGURATION
(TOP VIEW)
128Kx18 Synchronous SRAM
ADSC
ADSP
WEb
WEa
ADV
N.C.
N.C.
CLK
CS
1
CS
2
CS
2
GW
V
DD
BW
V
SS
OE
A
6
A
7
A
8
82
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
83
100
81
A
9
80
79
78
77
76
75
74
73
72
71
70
69
68
67
66
65
64
63
62
61
60
59
58
57
56
55
54
53
52
51
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
N.C.
N.C.
N.C.
N.C.
PIN NAME
SYMBOL
PIN NAME
Address Inputs
TQFP PIN NO.
32,33,34,35,36,37,
44,45,46,47,48,49,
80,81,82,99,100
83
84
85
89
98
97
92
93,94
86
88
87
64
31
SYMBOL
PIN NAME
Power Supply(+3.3V)
Ground
No Connect
N.C.
A
5
A
4
A
3
A
2
A
1
A
0
A
11
A
12
A
13
A
14
A
15
LBO
V
DD
V
SS
A
16
50
N.C.
N.C.
N.C.
V
DDQ
V
SSQ
N.C.
N.C.
DQb
0
DQb
1
V
SSQ
V
DDQ
DQb
2
DQb
3
N.C.
V
DD
N.C.
V
SS
DQb
4
DQb
5
V
DDQ
V
SSQ
DQb
6
DQb
7
DQPb
N.C.
V
SSQ
V
DDQ
N.C.
N.C.
N.C.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
100 Pin TQFP
(20mm x 14mm)
A
10
N.C.
N.C.
V
DDQ
V
SSQ
N.C.
DQPa
DQa
7
DQa
6
V
SSQ
V
DDQ
DQa
5
DQa
4
V
SS
N.C.
V
DD
ZZ
DQa
3
DQa
2
V
DDQ
V
SSQ
DQa
1
DQa
0
N.C.
N.C.
V
SSQ
V
DDQ
N.C.
N.C.
N.C.
TQFP PIN NO.
15,41,65,91
17,40,67,90
1,2,3,6,7,14,16,25,28,
29,30,38,39,42,43,50,
51,52,53,56,57,66,75,
78,79,95,96
58,59,62,63,68,69,72,73
8,9,12,13,18,19,22,23
74,24
4,11,20,27,54,61,70,77
5,10,21,26,55,60,71,76
A
0
- A
16
V
DD
V
SS
N.C.
ADV
ADSP
ADSC
CLK
CS
1
CS
2
CS
2
WEx
OE
GW
BW
ZZ
LBO
Burst Address Advance
Address Status Processor
Address Status Controller
Clock
Chip Select
Chip Select
Chip Select
Byte Write Inputs
Output Enable
Global Write Enable
Byte Write Enable
Power Down Input
Burst Mode Control
DQa
0
~a
7
DQb
0
~b
7
DQPa,Pb
V
DDQ
V
SSQ
Data Inputs/Outputs
Output Power Supply
(2.5V or 3.3V)
Output Ground
-3-
December 1998
Rev 3.0
KM718V787A
FUNCTION DESCRIPTION
128Kx18 Synchronous SRAM
The KM718V787A is a synchronous SRAM designed to support the burst address accessing sequence of the Pentium and Power
PC based microprocessor. All inputs(with the exception of OE, LBO and ZZ) are sampled on rising clock edges.
The start and duration of the burst access is controlled by ADSP, ADSC, ADV and Chip Select pins.
When ZZ is pulled HIGH, the SRAM will enter a Power Down State. At this time, internal state of the SRAM is preserved. When ZZ
returns to low, the SRAM normally operates after 2cycles of wake up time. ZZ pin is pulled down internally.
Read cycles are initiated with ADSP(or ADSC) using the new external address clocked into the on-chip address register when both
GW and BW are high or when BW is low and both WEa and WEb are high, When ADSP is sampled low, the chip selects are sam-
pled active, and the output buffer is enabled with OE, the data of cell array accessed by the current address are projected to the out-
put pins.
Write cycles are also initiated with ADSP(or ADSC) and are differentiated into two kinds of operations; All byte write operation and
individual byte write operation. All byte write occurs by enabling GW(in dependent of BW and WEx.), and individual byte write is per-
formed only when GW is High and BW is Low. WEa controls DQa
0
~ DQa
7
and DQPa, WEb controls DQb0 ~ DQb7 and DQPb.
CS
1
is used to enable the device and conditions internal use of ADSP and is sampled only when a new external address is loaded.
ADV is ignored at the clock edge when ADSP is asserted, but can be sampled on the subsequent clock edges. The address
increases internally for the next access of the burst when ADV is sampled low.
Addresses are generated for the burst access as shown below, The starting point of the burst sequence is provided by the external
address. The burst address counter wraps around to its initial state upon completion. The burst sequence is determined by the state
of the LBO pin. When this pin is low, linear burst sequence is selected. And when this pin is High, Interleaved burst sequence is
selected.
BURST SEQUENCE TABLE
LBO PIN
HIGH
First Address
Case 1
A
1
0
0
1
1
A
0
0
1
0
1
A
1
0
0
1
1
Case 2
A
0
1
0
1
0
A
1
1
1
0
0
Case 3
A
0
0
1
0
1
(Interleaved Burst)
Case 4
A
1
1
1
0
0
A
0
1
0
1
0
Fourth Address
BURST SEQUENCE TABLE
LBO PIN
LOW
First Address
Case 1
A
1
0
0
1
1
A
0
0
1
0
1
A
1
0
1
1
0
Case 2
A
0
1
0
1
0
A
1
1
1
0
0
Case 3
A
0
0
1
0
1
A
1
1
0
0
1
(Linear Burst)
Case 4
A
0
1
0
1
0
Fourth Address
Note :
1. LBO pin must be tied to high or low, and floating state must not be allowed.
ASYNCHRONOUS TRUTH TABLE
(See Notes 1 and 2)
:
OPERATION
Sleep Mode
Read
Write
Deselected
ZZ
H
L
L
L
L
OE
X
L
H
X
X
I/O STATUS
High-Z
DQ
High-Z
Din, High-Z
High-Z
Notes
1. X means "Don't Care".
2. ZZ pin is pulled down internally
3. For write cycles that following read cycles, the output buffersmust
be disabled with OE, otherwise data bus contention will occur.
4. Sleep Mode means power down state of which stand-by current
does not depend on cycle time.
5. Deselected means power down state of which stand-by current
depends on cycle time.
-4-
December 1998
Rev 3.0
KM718V787A
SYNCHRONOUS TRUTH TABLE
CS
1
H
L
L
L
L
L
L
L
X
H
X
H
X
H
X
H
CS
2
X
L
X
L
X
H
H
H
X
X
X
X
X
X
X
X
CS
2
X
X
H
X
H
L
L
L
X
X
X
X
X
X
X
X
ADSP ADSC
X
L
L
X
X
L
H
H
H
X
H
X
H
X
H
X
L
X
X
L
L
X
L
L
H
H
H
H
H
H
H
H
ADV
X
X
X
X
X
X
X
X
L
L
L
L
H
H
H
H
WRITE
X
X
X
X
X
X
L
H
H
H
L
L
H
H
L
L
CLK
↑
↑
↑
↑
↑
↑
↑
↑
↑
↑
↑
↑
↑
↑
↑
↑
128Kx18 Synchronous SRAM
ADDRESS ACCESSED
N/A
N/A
N/A
N/A
N/A
External Address
External Address
External Address
Next Address
Next Address
Next Address
Next Address
Current Address
Current Address
Current Address
Current Address
OPERATION
Not Selected
Not Selected
Not Selected
Not Selected
Not Selected
Begin Burst Read Cycle
Begin Burst Write Cycle
Begin Burst Read Cycle
Continue Burst Read Cycle
Continue Burst Read Cycle
Continue Burst Write Cycle
Continue Burst Write Cycle
Suspend Burst Read Cycle
Suspend Burst Read Cycle
Suspend Burst Write Cycle
Suspend Burst Write Cycle
Notes :
1. X means "Don
′
t Care".
2. The rising edge of clock is symbolized by
↑.
3. WRITE = L means Write operation in WRITE TRUTH TABLE.
WRITE = H means Read operation in WRITE TRUTH TABLE.
4. Operation finally depends on status of asynchronous input pins(ZZ and OE).
WRITE TRUTH TABLE
GW
H
H
H
H
H
L
BW
H
L
L
L
L
X
WEa
X
H
L
H
L
X
WEb
X
H
H
L
L
X
OPERATION
READ
READ
WRITE BYTE a
WRITE BYTE b
WRITE ALL BYTEs
WRITE ALL BYTEs
Notes :
1. X means "Don′t Care".
2. All inputs in this table must meet setup and hold time around the rising edge of CLK(↑).
编程基础
京公网安备 11010802033920号
Copyright © 2005-2026 EEWORLD.com.cn, Inc. All rights reserved
电子工程世界
