Integrated Device Technology Inc IDT71V256SB12PZ, IDT71V256SB12Y, IDT71V256SB15PZ, IDT71V256SB15Y, IDT71V256SB20PZ Datasheet
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Integrated Device Technology, Inc.
3.3V CMOS FAST SRAM
WITH 2.5V COMPATIBLE INPUTS
256K (32K x 8-BIT)
IDT71V256SB
FEATURES
• Ideal for high-performance processor secondary cache
• Fast access times:
— 12/15/20ns
• Inputs are 2.5V and LVTTL compatible: VIH = 1.8V
• Outputs are LVTTL compatible
• Low standby current (maximum):
— 2mA full standby
• Small packages for space-efficient layouts:
— 28-pin 300 mil SOJ
— 28-pin TSOP Type I
• Produced with advanced high-performance CMOS
technology
• Single 3.3V(±0.3V) power supply
FUNCTIONAL BLOCK DIAGRAM
DESCRIPTION
The IDT71V256SB is a 262,144-bit high-speed static RAM
organized as 32K x 8. The improved VIH (1.8V) makes the
inputs compatible with 2.5V logic levels. The IDT71V256SB
is otherwise identical to the IDT71V256SA.
The IDT71V256SB has outstanding low power characteristics while at the same time maintaining very high performance. Address access times of as fast as12 ns are ideal for
tag SRAM in secondary cache designs.
When power management logic puts the IDT71V256SB in
standby mode, its very low power characteristics contribute to
extended battery life. By taking CS HIGH, the SRAM will
automatically go to a low power standby mode and will remain
in standby as long as CS remains HIGH. Furthermore, under
full standby mode (CS at CMOS level, f=0), power consumption is guaranteed to always be less than 6.6mW and typically
will be much smaller.
The IDT71V256SB is packaged in 28-pin 300 mil SOJ and
28-pin300 mil TSOP Type I packaging.
A
I/O
I/O
A
14
0
0
7
CS
OE
WE
CONTROL
CIRCUIT
ADDRESS
DECODER
INPUT
DATA
CIRCUIT
262,144 BIT
MEMORY ARRAY
I/O CONTROL
V
CC
GND
3770 drw 01
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
COMMERCIAL TEMPERATURE RANGES JANUARY 1997
1997 Integrated Device Technology, Inc. 3770/1
7.??
1
IDT71V256SB
3.3V CMOS STATIC RAM WITH 2.5V COMPATIBLE INPUTS 256K (32K x 8-BIT) COMMERCIAL TEMPERATURE RANGE
PIN CONFIGURATIONS ABSOLUTE MAXIMUM RATINGS
A
A
A
A
A
A
A
A
A
A
I/O
I/O
I/O
GND
1
14
2
12
3
7
4
6
5
5
6
4
3
2
1
0
0
1
2
7
8
9
10
11
12
13
14
SO28-5
SOJ
28
V
CC
27
WE
26
A
13
25
8
A
24
A
9
23
A
11
22
OE
21
10
A
20
CS
19
18
17
16
15
7
I/O
6
I/O
I/O
5
I/O
4
I/O
3
3770 drw 02
TOP VIEW
22
OE
23
11
A
24
A
9
25
A
8
26
A
13
27
WE
28
V
CC
1
A
14
2
A
12
3
A
7
4
A
6
5
A
5
6
A
4
7
A
3
SO28-8
TSOP
21
20
19
18
17
16
15
14
13
12
11
10
9
8
A
10
CS
7
I/O
I/O
6
I/O
5
I/O
4
I/O
3
GND
I/O
2
I/O
1
I/O
0
A
0
A
1
A
2
3770 drw 03
TOP VIEW
Symbol Rating Com’l. Unit
(2)
V
TERM
Terminal Voltage with –0.5 to +4.6 V
Respect to GND
(3)
V
TERM
Terminal Voltage with –0.5 to VCC+0.5 V
Respect to GND
T
A Operating Temperature 0 to +70 °C
T
BIAS Temperature Under Bias –55 to +125 °C
STG Storage Temperature –55 to +125 °C
T
P
T Power Dissipation 1.0 W
I
OUT DC Output Current 50 mA
NOTES: 3770 tbl 03
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. Vcc terminals only.
3. Input, Output, and I/O terminals; 4.6V maximum.
CAPACITANCE
(TA = +25°C, f = 1.0MHz, SOJ package)
Symbol Parameter
C
IN Input Capacitance VIN = 3dV 6 pF
C
OUT Output Capacitance VOUT = 3dV 7 pF
NOTE: 3770 tbl 04
1. This parameter is determined by device characterization, but is not
production tested.
(1)
Conditions Max. Unit
(1)
PIN DESCRIPTIONS
Name Description
A
0–A14 Addresses
I/O
0–I/O7 Data Input/Output
CS
WE
OE
GND Ground
V
CC Power
TRUTH TABLE
WE
WE
X H X High-Z Standby (ISB)
XV
H L H High-Z Output Disable
HLLD
LLXD
NOTE: 3770 tbl 02
1. H = VIH, L = VIL, X = Don’t Care
CS
CS
HC X High-Z Standby (ISB1)
Chip Select
Write Enable
Output Enable
(1)
OE
OE
3770 tbl 01
I/O Function
OUT Read
IN Write
RECOMMENDED OPERATING
TEMPERATURE AND SUPPLY VOLTAGE
Grade Temperature GND VCC
Commercial 0°C to +70°C 0V 3.3V ± 0.3V
3770 tbl 05
RECOMMENDED DC OPERATING
CONDITIONS
Symbol Parameter Min. Typ. Max. Unit
VCC Supply Voltage 3.0 3.3 3.6 V
GND Supply Voltage 0 0 0 V
VIH Input High Voltage - Inputs 1.8 — 5.0 V
VIH Input High Voltage - I/O 1.8 — Vcc+0.3 V
V
IL Input Low Voltage –0.5
NOTE: 3770 tbl 06
1. VIL (min.) = –1.0V for pulse width less than 5ns, once per cycle.
(1)
— 0.8 V
2
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