128K X 36, 256K X 18
3.3V Sychronous SRAMs
2.5V I/O, Pipelined Outputs,
Burst Counter, Single Cycle Deselect
x
x
Preliminary
IDT71V2576
IDT71V2578
Features
x
x
x
x
x
x
128K x 36, 256K x 18 memory configurations
Supports high system speed:
200MHz 3.1ns clock access time
183MHz 3.3ns clock access time
166MHz 3.5ns clock access time
150MHz 3.8ns clock access time
133MHz 4.2ns clock access time
LBO
input selects interleaved or linear burst mode
Self-timed write cycle with global write control (GW), byte write
enable (BWE), and byte writes (BWx)
3.3V core power supply
Power down controlled by ZZ input
2.5V I/O
Packaged in a JEDEC Standard 100-lead plastic thin quad
flatpack (TQFP) and 119-lead ball grid array (BGA)
Description
The IDT71V2576/78 are high-speed SRAMs organized as 128K x
36/256K x 18. The IDT71V2576/78 SRAMs contain write, data, address
and control registers. Internal logic allows the SRAM to generate a self-
timed write based upon a decision which can be left until the end of the write
cycle.
The burst mode feature offers the highest level of performance to the
system designer, as the IDT71V2576/78 can provide four cycles of data
for a single address presented to the SRAM. An internal burst address
counter accepts the first cycle address from the processor, initiating the
access sequence. The first cycle of output data will be pipelined for one
cycle before it is available on the next rising clock edge. If burst mode
operation is selected (ADV=LOW), the subsequent three cycles of output
data will be available to the user on the next three rising clock edges. The
order of these three addresses are defined by the internal burst counter
and the
LBO
input pin.
The IDT71V2576/78 SRAMs utilize IDTs latest high-performance
CMOS process and are packaged in a JEDEC standard 14mm x 20mm
100-lead thin plastic quad flatpack (TQFP) as well as a 119-lead ball grid
array (BGA).
Pin Description Summary
A
0
-A
17
CE
CS
0
,
CS
1
OE
GW
BWE
BW
1
,
BW
2
,
BW
3
,
BW
4
(1)
CLK
ADV
ADSC
ADSP
LBO
ZZ
I/O
0
-I/O
31
, I/O
P1
-I/O
P4
V
DD
, V
DDQ
V
SS
Address Inputs
Chip Enable
Chip Selects
Output Enable
Global Write Enable
Byte Write Enable
Individual Byte Write Selects
Clock
Burst Address Advance
Address Status (Cache Controller)
Address Status (Processor)
Linear / Interleaved Burst Order
Sleep Mode
Data Input / Output
Core Power, I/O Power
Ground
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
Input
I/O
Supply
Supply
Synchronous
Synchronous
Synchronous
Asynchronous
Synchronous
Synchronous
Synchronous
N/A
Synchronous
Synchronous
Synchronous
DC
Asynchronous
Synchronous
N/A
N/A
4876 tbl 01
NOTE:
1.
BW
3
and
BW
4
are not applicable for the IDT71V2578.
SEPTEMBER 1999
1
©1999 Integrated Device Technology, Inc.
DSC-4876/5
IDT71V2576, IDT71V2578, 128K x 36, 256K x 18, 3.3V Synchronous SRAMS with
2.5V I/O, Pipelined Outputs, Burst Counter, Single Cycle Deselect
Preliminary
Commercial Temperature Range
Pin Definitions
(1)
Symbol
A
0
-A
17
ADSC
ADSP
ADV
Pin Function
Address Inputs
Address Status
(Cache Controller)
Address Status
(Processor)
Burst Address
Advance
Byte Write Enable
I/O
I
I
I
I
Active
N/A
LOW
LOW
LOW
Description
Synchronous Address inputs. The address register is triggered by a combination of the
rising edge of CLK and
ADSC
Low or
ADSP
Low and
CE
Low.
Synchronous Address Status from Cache Controller.
ADSC
is an active LOW input that is
used to load the address registers with new addresses.
Synchronous Address Status from Processor.
ADSP
is an active LOW input that is used to
load the address registers with new addresses.
ADSP
is gated by
CE.
Synchronous Address Advance.
ADV
is an active LOW input that is used to advance the
internal burst counter, controlling burst access after the initial address is loaded. When the
input is HIGH the burst counter is not incremented; that is, there is no address advance.
Synchronous byte write enable gates the byte write inputs
BW
1
-BW
4
. If
BWE
is LOW at the
rising edge of CLK then
BWx
inputs are passed to the next stage in the circuit. If
BWE
is
HIGH then the byte write inputs are blocked and only
GW
can initiate a write cycle.
Synchronous byte write enables.
BW
1
controls I/O
0-7
, I/O
P1
,
BW
2
controls I/O
8-15
, I/O
P2
, etc.
Any active byte write causes all outputs to be disabled.
Synchronous chip enable.
CE
is used with CS
0
and
CS
1
to enable the IDT71V2576/78.
CE
also gates
ADSP.
This is the clock input. All timing references for the device are made with respect to this
input.
Synchrono us active HIGH chip select. CS
0
is used with
CE
and
CS
1
to enable the chip.
Synchronous active LOW chip select.
CS
1
is used with
CE
and CS
0
to enable the chip.
Synchronous global write enable. This input will write all four 9-bit data bytes when LOW
on the rising edge of CLK.
GW
supersedes individual byte write enables.
Synchronous data input/output (I/O) pins. Both the data input path and data output path are
registered and triggered by the rising edge of CLK.
Asynchronous burst order selection input. When
LBO
is HIGH, the interleaved burst
sequence is selected. When
LBO
is LOW the Linear burst sequence is selected.
LBO
is a
static input and must not change state while the device is operating.
Asynchronous output enable. When
OE
is LOW the data output drivers are enabled on the
I/O pins if the chip is also selected. When
OE
is HIGH the I/O pins are in a high-
impedance state.
3.3V core power supply.
2.5V I/O Supply.
Ground.
NC pins are not electrically connected to the device.
Asynchronous sleep mode input. ZZ HIGH will gate the CLK internally and power down the
IDT71V2576/78 to its lowest power consumption level. Data retention is guaranteed in
Sleep Mode.
4876 tbl 02
BWE
I
LOW
BW
1
-BW
4
CE
CLK
CS
0
CS
1
GW
I/O
0
-I/O
31
I/O
P1
-I/O
P4
LBO
Individual Byte
Write Enables
Chip Enable
Clock
Chip Select 0
Chip Select 1
Global Write
Enable
Data Input/Output
Linear Burst Order
I
I
I
I
I
I
I/O
I
LOW
LOW
N/A
HIGH
LOW
LOW
N/A
LOW
OE
Output Enable
I
LOW
V
DD
V
DDQ
V
SS
NC
ZZ
Power Supply
Power Supply
Ground
No Connect
Sleep Mode
N/A
N/A
N/A
N/A
I
N/A
N/A
N/A
N/A
HIGH
NOTE:
1. All synchronous inputs must meet specified setup and hold times with respect to CLK.
6.42
2
IDT71V2576, IDT71V2578, 128K x 36, 256K x 18, 3.3V Synchronous SRAMS with
2.5V I/O, Pipelined Outputs, Burst Counter, Single Cycle Deselect
Preliminary
Commercial Temperature Range
Functional Block Diagram
LBO
ADV
CEN
Burst
Sequence
INTERNAL
ADDRESS
CLK
ADSC
ADSP
CLK EN
ADDRESS
REGISTER
Byte 1
Write Register
Binary
Counter
CLR
2
Burst
Logic
17/18
A0*
A1*
Q0
Q1
128K x 36/
256K x 18-
BIT
MEMORY
ARRAY
2
A
0
,A
1
17/18
A
2 -
A
17
36/18
36/18
A
0 -
A
16/17
GW
BWE
BW
1
Byte 1
Write Driver
9
Byte 2
Write Register
Byte 2
Write Driver
BW
2
Byte 3
Write Register
9
Byte 3
Write Driver
BW
3
Byte 4
Write Register
9
Byte 4
Write Driver
BW
4
9
OUTPUT
REGISTER
CE
CS
0
CS
1
D
Q
Enable
Register
DATA INPUT
REGISTER
CLK EN
ZZ
Powerdown
D
Q
Enable
Delay
Register
OE
OUTPUT
BUFFER
OE
I/O
0
— I/O
31
I/O
P1
— I/O
P4
36/18
,
4876 drw 01
6.42
3
IDT71V2576, IDT71V2578, 128K x 36, 256K x 18, 3.3V Synchronous SRAMS with
2.5V I/O, Pipelined Outputs, Burst Counter, Single Cycle Deselect
Preliminary
Commercial Temperature Range
Absolute Maximum Ratings
(1)
Symbol
V
TERM
(2)
V
TERM
(3,6)
Rating
Terminal Voltage with
Respect to GND
Terminal Voltage with
Respect to GND
Terminal Voltage with
Respect to GND
Terminal Voltage with
Respect to GND
Operating Temperature
Temperature
Under Bias
Storage
Temperature
Power Dissipation
DC Output Current
Commercial
-0.5 to +4.6
-0.5 to V
DD
-0.5 to V
DD
+0.5
-0.5 to V
DDQ
+0.5
-0 to +70
-55 to +125
-55 to +125
2.0
50
Unit
V
V
V
V
o
Recommended Operating
Temperature and Supply Voltage
Grade
Commercial
Temperature
0°C to +70°C
V
SS
0V
V
DD
3.3V±5%
V
DDQ
2.5V±5%
4876 tbl 04
V
TERM
(4,6)
V
TERM
(5,6)
T
A
T
BIAS
T
STG
P
T
I
OUT
C
C
C
Recommended DC Operating
Conditions
Symbol
Parameter
Core Supply Voltage
I/O Supply Voltage
Supply Voltage
Input High Voltage -
Inputs
Input High Voltage - I/O
Input Low Voltage
Min.
3.135
2.375
0
1.7
1.7
-0.3
(2)
Typ.
3.3
2.5
0
____
Max.
3.465
2.625
0
V
DD
+0.3
V
DDQ
+0.3
(1)
0.7
Unit
V
V
V
V
V
V
4876 tbl 05
o
V
DD
V
DDQ
V
SS
V
IH
V
IH
V
IL
o
W
mA
4876 tbl 03
____
NOTES:
1. Stresses greater than those listed under ABSOLUTE MAXIMUM RATINGS may
cause permanent damage to the device. This is a stress rating only and functional
operation of the device at these or any other conditions above those indicated
in the operational sections of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect reliability.
2. V
DD
terminals only.
3. V
DDQ
terminals only.
4. Input terminals only.
5. I/O terminals only.
6. This is a steady-state DC parameter that applies after the power supplies have
ramped up. Power supply sequencing is not necessary; however, the voltage
on any input or I/O pin cannot exceed V
DDQ
during power supply ramp up.
____
NOTES:
1. V
IH
(max) = V
DDQ
+ 1.0V for pulse width less than t
CYC/2
, once per cycle.
2. V
IL
(min) = -1.0V for pulse width less than t
CYC/2
, once per cycle.
Capacitance
Symbol
C
IN
C
I/O
(T
A
= +25°C, f = 1.0MHz)
Parameter
(1)
Input Capacitance
I/O Capacitance
Conditions
V
IN
= 3dV
V
OUT
= 3dV
Max.
5
7
Unit
pF
pF
4876 tbl 07
NOTE:
1. This parameter is guaranteed by device characterization, but not production
tested.
6.42
4
IDT71V2576, IDT71V2578, 128K x 36, 256K x 18, 3.3V Synchronous SRAMS with
2.5V I/O, Pipelined Outputs, Burst Counter, Single Cycle Deselect
Preliminary
Commercial Temperature Range
Pin Configuration 128K x 36 TQFP
A
6
A
7
CE
CS
0
BW
4
BW
3
BW
2
BW
1
CS
1
V
DD
V
SS
CLK
GW
BWE
OE
ADSC
ADSP
ADV
A
8
A
9
100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85 84 83 82 81
I/O
P3
I/O
16
I/O
17
V
DDQ
V
SS
I/O
18
I/O
19
I/O
20
I/O
21
V
SS
V
DDQ
I/O
22
I/O
23
V
DD
/NC
(1)
V
DD
NC
V
SS
I/O
24
I/O
25
V
DDQ
V
SS
I/O
26
I/O
27
I/O
28
I/O
29
V
SS
V
DDQ
I/O
30
I/O
31
I/O
P4
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
31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
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
I/O
P2
I/O
15
I/O
14
V
DDQ
V
SS
I/O
13
I/O
12
I/O
11
I/O
10
V
SS
V
DDQ
I/O
9
I/O
8
V
SS
NC
V
DD
ZZ
(3)
I/O
7
I/O
6
V
DDQ
V
SS
I/O
5
I/O
4
I/O
3
I/O
2
V
SS
V
DDQ
I/O
1
I/O
0
I/O
P1
4876 drw 02
,
LBO
A
5
A
4
A
3
A
2
A
1
A
0
NOTES:
1. Pin 14 can either be directly connected to V
DD
, or connected to an input voltage
≥
V
IH
, or left unconnected.
2. Pins 38 and 39 can be either NC or connected to V
SS.
3. Pin 64 can be left unconnected and the device will always remain in active mode.
Top View
NC
(2)
NC
(2)
V
SS
V
DD
NC
NC
A
10
A
11
A
12
A
13
A
14
A
15
A
16
6.42
5
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