NOVEMBER 2014
DSC-2948/11
1
©2014 Integrated Device Technology, Inc.
Features
◆◆
◆◆
◆32K x 8 advanced high-speed CMOS static RAM
◆◆
◆◆
◆Commercial (0° to 70°C) and Industrial (-40° to 85°C)
temperature options
◆◆
◆◆
◆Equal access and cycle times
– Commercial: 12ns
– Commercial and Industrial: 15/20/25ns
◆◆
◆◆
◆One Chip Select plus one Output Enable pin
◆◆
◆◆
◆Bidirectional data inputs and outputs directly
TTL-compatible
◆◆
◆◆
◆Low power consumption via chip deselect
◆◆
◆◆
◆Commercial product available in 28-pin 300-mil Plastic DIP,
300 mil Plastic SOJ and TSOP packages
◆◆
◆◆
◆Industrial product available in 28-pin 300 mil Plastic SOJ
and TSOP packages
Description
The IDT71256SA is a 262,144-bit high-speed Static RAM
organized as 32K x 8. It is fabricated using high-performance, high-
reliability CMOS technology. This state-of-the-art technology, com-
bined with innovative circuit design techniques, provides a cost-
effective solution for high-speed memory needs.
The IDT71256SA has an output enable pin which operates as fast
as 6ns, with address access times as fast as 12ns. All bidirectional
inputs and outputs of the IDT71256SA are TTL-compatible and
operation is from a single 5V supply. Fully static asynchronous
circuitry is used, requiring no clocks or refresh for operation.
The IDT71256SA is packaged in 28-pin 300-mil Plastic DIP, 28-
pin 300 mil Plastic SOJ and TSOP.
Functional Block Diagram
CMOS Static RAM
256K (32K x 8-Bit) IDT71256SA
A
0
A
1
A
2
A
3
A
4
A
5
A
6
A
7
A
8
A
9
A
10
A
11
A
12
A
13
A
14
I/O
0-
I/O
7
CS
WE
OE
8 8
CONTROL
LOGIC
I/O CONTROL
262,144-BIT
MEMORY
ARRAY
ADDRESS
DECODER
2948 drw 01
,
2
IDT71256SA
CMOS Static RAM 256K (32K x 8-Bit) Commercial and Industrial Temperature Ranges
Absolute Maximum Ratings(1)
Pin Configurations
DIP/SOJ
Top View
Recommended Operating
Temperature and Supply Voltage Recommended DC Operating
Conditions
Truth Table(1,2)
TSOP
Top View
NOTE:
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.
Symbol Rating Value Unit
V
CC
Supply Voltage
Re lativ e to GND -0.5 to +7.0 V
V
TERM
Terminal Voltag e
Re lativ e to GND -0.5 to V
CC
+0.5 V
T
BIAS
Te mperature Unde r Bias -55 to +125
o
C
T
STG
Storage Te mpe rature -55 to +125
o
C
P
T
Po we r Di ss ip atio n 1. 0 W
I
OUT
DC Output Curre nt 50 mA
2948 tbl 02
NOTES:
1 . H = VIH, L = VIL, x = Don't care.
2. VLC = 0.2V, VHC = VCC –0.2V.
3. Other inputs ≥VHC or ≤VLC.
CS OE WE I/O Fun ction
LLHDATA
OUT
Re ad Data
LXLDATA
IN
Wri te Data
L H H High-Z Outputs Disabled
H X X High-Z Deselected - Standby (I
SB
)
V
HC
(3)
X X Hi gh-Z Des elec ted - Sta ndby ( I
SB1
)
2948 t bl 03
Grade Temperature GND Vcc
Commercial 0
O
C to + 70
O
C 0V 4.5V ± 5.5V
Industrial -40
O
C to + 85
O
C 0V 4.5V ± 5.5V
2948 tbl 01
NOTE:
1. VIL (min.) = –1.5V for pulse width less than 10ns, once per cycle.
Symbol Parameter Min. Typ. Max. Unit
V
CC
Supply Voltage 4.5 5.0 5.5 V
GND Ground 0 0 0 V
V
IH
Inp ut Hig h Vo ltag e 2. 2
____
V
CC
+0.5 V
V
IL
Inp ut Lo w Vo ltag e -0. 5
(1)
____
0.8 V
2 948 t bl 04
WE
CS
2948 drw 02
5
6
7
8
9
10
11
12
GND
1
2
3
4
24
23
22
21
20
19
18
17
SO28
P28
13
14
28
27
26
25
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
I/O
0
I/O
1
I/O
2
V
CC
A
14
A
13
A
8
A
10
A
11
OE
A
12
I/O
7
I/O
6
I/O
5
I/O
4
I/O
3
A
9
16
15
2948 drw 02a
22
23
24
25
26
27
28
1
2
3
4
5
7
6
21
20
19
18
17
16
15
14
13
12
11
10
9
8
A
10
CS
I/O
7
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
SO28
OE
A
11
A
9
A
8
A
13
A
14
A
7
A
6
A
5
A
4
A
3
A
12
WE
V
CC
,
6.42
IDT71256SA
CMOS Static RAM 256K (32K x 8-Bit) Commercial and Industrial Temperature Ranges
3
Figure 2. AC Test Load
(for tCLZ, tOLZ, tCHZ, tOHZ, tOW, and tWHZ)
Figure 1. AC Test Load
*Including jig and scope capacitance.
DC Electrical Characteristics(1)
(VCC = 5.0V ± 10%, VLC = 0.2V, VHC = VCC–0.2V)
AC Test Conditions Capacitance
(TA = +25°C, f = 1.0MHz, SOJ package)
DC Electrical Characteristics
(VCC = 5.0V ± 10%)
2948 drw 03
480Ω
255Ω30pF*
DATA
OUT
5V
,
2948 drw 04
480Ω
255Ω5pF*
DATA
OUT
5V
.
Symbol Parameter Test Conditions
IDT71256SA
UnitMin. Max.
|I
LI
| Input Le akag e Curre nt V
CC
= Max., V
IN
=
GND to V
CC
___
5µA
|I
LO
| Output Le akag e Curre nt V
CC
= Max., CS = V
IH
, V
OUT
= GND to V
CC
___
5µA
V
OL
Output Lo w Vo ltag e I
OL
= 8mA, V
CC
= Min.
___
0.4 V
V
OH
Outp ut Hig h Voltag e I
OH
= -4mA, V
CC
= Min. 2.4
___
V
2948 tbl 05
NOTES:
1. All values are maximum guaranteed values.
2. fMAX = 1/tRC (all address inputs are cycling at fMAX); f = 0 means no address input lines are changing.
Symbol Parameter 71256SA12 71256SA15 71256SA20 71256SA25 Unit
I
CC
Dynamic Operating Current
CS < VIL, Outputs Open, VCC = Max ., f = fMAX
(2)
160 150 145 145 mA
I
SB
Standb y Power Supp ly Current (TTL Level)
CS > VIH, Outputs Open, VCC = Max ., f = fMAX
(2)
50 40 40 40 mA
I
SB1
Standby Power Supply Current (CMOS Level)
CS > VHC, Outputs Open, VCC = Max. , f = 0
(2)
,
VIN < VLC or VIN > VHC
15 15 15 15 mA
2948 tbl 06
Input Pulse Levels
Inp ut Ris e /Fal l Time s
Input Timing Refe rence Leve ls
Outp ut Re fere nce Lev e ls
AC Test Load
GND to 3.0V
3ns
1.5V
1.5V
See Figures 1 and 2
2948 tbl 07
NOTE:
1. This parameter is guaranteed by device characterization, but not production
tested.
Symbol Parameter
(1)
Conditions Max. Unit
C
IN
Inp ut Cap ac itanc e V
IN
= 3dV 7 pF
C
I/O
I/O Cap ac itanc e V
OUT
= 3dV 7 pF
2948 tbl 08
4
IDT71256SA
CMOS Static RAM 256K (32K x 8-Bit) Commercial and Industrial Temperature Ranges
AC Electrical Characteristics (VCC = 5.0V ± 10%)
NOTE:
1. This parameter is guaranteed with the AC Load (Figure 2) by device characterization, but is not production tested.
Symbol Parameter
71256SA12 71256SA15 71256SA20 71256SA25
Unit
Min. Max. Min. Max. Min. Max. Min. Max.
Read Cycle
t
RC
Re ad Cy c le Tim e 12
____
15
____
20
____
25
____
ns
t
AA
Address Access Time
____
12
____
15
____
20
____
25 ns
t
ACS
Chip Select Access Time
____
12
____
15
____
20
____
25 ns
t
CLZ
(1)
Chip Select to Output in Low-Z 4
____
4
____
4
____
4
____
ns
t
CHZ
(1)
Chip Sele ct to Outp ut in High-Z 0 6 0 7 0 10 0 11 ns
t
OE
Outp u t Ena b le to O utp ut Val id
____
6
____
7
____
10
____
11 ns
t
OLZ
(1)
Outp ut E nable to Outp ut in Lo w-Z 0
____
0
____
0
____
0
____
ns
t
OHZ
(1)
Output Disable to Output in High-Z 060608010ns
t
OH
Outp ut Ho ld fro m A dd res s Chang e 3
____
3
____
3
____
3
____
ns
t
PU
(1)
Chip Se lect to Po we r Up Time 0
____
0
____
0
____
0
____
ns
t
PD
(1)
Chip Deselect to Pow er D own Ti m e
____
12
____
15
____
20
____
25 ns
Wri te Cycl e
t
WC
Write Cycle Time 12
____
15
____
20
____
25
____
ns
t
AW
Address Valid to End-of-Write 9
____
10
____
15
____
20
____
ns
t
CW
Chip Select to End-of-Write 9
____
10
____
15
____
20
____
ns
t
AS
Address Set-up Time 0
____
0
____
0
____
0
____
ns
t
WP
Write P ulse Wid th 8
____
10
____
15
____
20
____
ns
t
WR
Write Recovery Time 0
____
0
____
0
____
0
____
ns
t
DW
Data Valid to End -of-Write 6
____
7
____
11
____
13
____
ns
t
DH
Data Ho ld Time 0
____
0
____
0
____
0
____
ns
t
OW
(1)
Outp ut Ac tiv e fro m End -o f-Wri te 4
____
4
____
4
____
4
____
ns
t
WHZ
(1)
Write Enable to Output in Hi gh-Z 0 6 0 6 0 10 0 11 ns
2948 tbl 09
6.42
IDT71256SA
CMOS Static RAM 256K (32K x 8-Bit) Commercial and Industrial Temperature Ranges
5
Timing Waveform of Read Cyc le No. 1(1)
ADDRESS
OE
CS
DATA
OUT
V
CC
SUPPLY
CURRENT
2948 drw 05
(5) (5)
(5)
(5)
DATA VALID
HIGH IMPEDANCE
t
AA
t
RC
t
OE
t
ACS
t
OLZ
t
CHZ
t
CLZ
(3)
t
OHZ
OUT
t
PU
t
PD
I
CC
I
SB
,
Timing Waveform of Read Cy cle No. 2(1,2,4)
NOTES:
1. WE is HIGH for Read Cycle.
2. Device is continuously selected, CS is LOW.
3. Address must be valid prior to or coincident with the later of CS transition LOW; otherwise tAA is the limiting parameter.
4. OE is LOW.
5. Transition is measured ±200mV from steady state.
DATA
OUT
ADDRESS
2948 drw 06
t
RC
t
AA
t
OH
t
OH
DATA
OUT
VALID
PREVIOUS DATA
OUT
VALID
,
6
IDT71256SA
CMOS Static RAM 256K (32K x 8-Bit) Commercial and Industrial Temperature Ranges
Timing Wa vef orm of Write Cyc le No. 1 (WE Controlled Timing)(1,2,4)
NOTES:
1. A write occurs during the overlap of a LOW CS and a LOW WE.
2. OE is continuously HIGH. If during a WE controlled write cycle OE is LOW, tWP must be greater than or equal to tWHZ + tDW to allow the I/O drivers to turn off and data
to be placed on the bus for the required tDW. If OE is HIGH during a WE controlled write cycle, this requirement does not apply and the minimum write pulse is as
short as the specified tWP.
3. During this period, I/O pins are in the output state, and input signals must not be applied.
4. If the CS LOW transition occurs simultaneously with or after the WE LOW transition, the outputs remain in a high-impedance state.
5. Transition is measured ±200mV from steady state.
Timing Wa veform of Write Cy cle No. 2 (CS Controlled Timing)(1,4)
ADDRESS
CS
WE
DATA
OUT
DATA
IN
2948 drw 07
(5)
(3) (3)
(2)
(5) (5)
DATA
IN
VALID
HIGH IMPEDANCE
t
WC
t
AS
t
WHZ
t
WP
t
CHZ
t
OW
t
DW
t
WR
t
AW
t
DH
,
CS
ADDRESS
WE
2948 drw 08
DATA
IN
VALID
t
AW
t
WC
t
CW
t
AS
t
WR
t
DW
t
DH
DATA
IN ,
6.42
IDT71256SA
CMOS Static RAM 256K (32K x 8-Bit) Commercial and Industrial Temperature Ranges
7
Ordering Information
NOTE:
1. Available in commercial temperature range only.
SA
Power
XX
Speed
XXX
Package
X
Process/
Temperature
Range
Blank
I
Commercial (0°C to +70°C)
Industrial (-40°C to +85°C)
TP
Y
PZ
300-mil Plastic DIP (P28)
300-mil SOJ (SO28)
TSOP Type I (SO28)
12
15
20
25
71256
Device
Type
Speed in nanoseconds
2948 drw 09
X
GGreen
Blank
8
Tube or Tray
Tape and Reel
X
(1)
8
IDT71256SA
CMOS Static RAM 256K (32K x 8-Bit) Commercial and Industrial Temperature Ranges
Datasheet Document History
1/7/00 Updated to new format
Pg. 1, 3, 4, 7 Revised Industrial Temperature range offerings
Pg. 6 Removed Note No. 1 for Write Cycle diagrams, renumbered footnotes and notes
Pg. 8 Added Datasheet Document History
08/09/00 Not recommended for new designs
02/01/01 Removed "Not recommended for new designs"
09/30/04 Pg. 7 Added "Restricted hazardous substance device" to ordering informations.
02/20/07 Pg. 7 Added TT generation die step to data sheet ordering information.
04/28/11 Pg. 1, 2, 7 Obsoleted 28-pin 600 mil and removed TT generation die step from Ordering information.
Added Tape and Reel to Ordering information and updated description of Restricted
hazardous substance device to Green
11/03/14 Pg. 1 & 8 Removed 12ns I-temp offering in Features. Added note regarding 12ns commercial only on
the Ordering information page. Removed IDT as a reference for fabrication in Description.
Pg. 2 & 8 Removed package extensions from pinouts and from Ordering information.
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
CORPORATE HEADQUARTERS for SALES:
6024 Silver Creek Valley Road 800-345-7015 or
San Jose, CA 95138 408-284-8200
fax: 408-284-2775
www.idt.com
for Tech Support:
sramhelp@idt.com
408-284-4532
