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CY62256
32Kx8 Static RAM
Features
output enable (OE) and three-state drivers. This device has an
automatic power-down feature, reducing the power consump-
tion by 99.9% when deselected. The CY62256 is in the stan-
dard 450-mil-wide (300-mil body width) SOIC, TSOP, and
600-mil PDIP packages.
An active LOW write enable signal (WE) co ntrol s th e writ-
ing/reading operation of the memory. When CE and WE inputs
are both LOW, data on the eight data input/output pins (I/O 0
through I/O 7 ) is written into the memory location addressed by
the address present on the address pins (A 0 through A 14 ).
Reading the device is ac com plish ed b y selecting the de vice
and enabling the outputs, CE and OE active LOW, while WE
remains inactive or HIGH. Under these conditions, the con-
tents of the location addressed by the information on address
pins are present on the eight data input/output pins.
The input/output pins remain in a high-impedance state unless
t he c hip is selected, outputs are enabled, and write enable
(WE) is HIGH.
W (max.)
• 55, 70 ns access time
• Easy memory expansion with CE and OE features
• TTL-compatible inputs and outputs
• Automatic power-down when deselected
• CMOS for optimum speed/power
Functional Description
m
The CY62256 is a high-performance CMOS static RAM orga-
nized as 32,768 words by 8 bits. Easy mem ory expansion is
provided by an active LOW chip enable (CE) and active LOW
Logic Block Diagram
Pin Configurations
SOIC/DIP
A 5
1
2
3
4
5
6
7
8
9
10
11
28
27
26
V CC
A 6
A 7
A 8
A 9
A 10
A 11
A 12
A 13
WE
I/O 0
A A 3
A 2
A 1
25
INPUTBUFFER
24
23
22
A 10
I/O 1
A 9
A 8
A A A 5
A A 3
A 2
OE
A 0
I/O 2
21
20
19
18
17
CE
I/O 3
512x512
ARRAY
A 14
I/O 7
I/O 6
I/O 5
I/O 4
I/O 0
I/O 1
I/O 2
I/O 4
12
13
16
I/O 5
GND
14
15
I/O 3
C62256–2
CE
I/O 6
WE
COLUMN
DECODER
POWER
DOWN
I/O 7
OE
C62256–1
A 11
7
6
8
9
A 12
OE
A 1
A 2
A A 4
WE
V C A A 6
A A 8
A 9
22
23
24
25
26
27
28
1
2
21
A 0
CE
I/O 7
I/O 6
I/O 5
A 10
A 13
20
A 14
A 9
5
10
11
19
18
17
A 8
I/O 0
4
A 7
3
TSOP I
12
I/O 1
I/O 4
A 6
13
I/O 2
TSOP I
Top View
(not to scale)
16
2
Reverse Pinout
I/O 3
A 5
1
14
GND
15
14
13
12
Top View
(not to scale)
GND
I/O 2
I/O 1
V CC
28
15
I/O 3
WE
27
16
I/O 4
A 4
26
17
I/O 5
3
4
I/O 0
A 14
A 3
25
18
I/O 6
11
A 2
24
19
I/O 7
5
10
9
A 13
A 12
C62256–3
A 1
23
20
21
CE
A 10
A 11
6
OE
22
A 0
7
8
C62256–4
Cypress Semiconductor Corporation • 3901 North First Street • San Jose • CA 95134 • 408-943-2600
March 1996 – Revised November 26, 1997
• 4.5V–5.5V Operation
• Low active power (70 ns, LL version)
— 275 mW (max.)
• Low standby power (70 ns, LL version)
28
Top V i ew
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CY62256
Maximum Ratings
Output Current into Outputs (LOW)............................. 20 mA
Static Discharge Voltage .......................................... >2001V
(per MIL-STD-883, Method 3015)
Latch-Up Current.................................................... >200 mA
(Above which the useful life may be impaired. For user guide-
lines, not tested.)
Storage Temperature
..................................... -
65
°
C to +150
°
C
Ambient Temperature with
Power Applied ................................................... 0
°
C to +70
°
C
Operating Range
Range
Ambient Temperature
V CC
Supply Voltage to Ground Potential
(Pin 28 to Pin 14)
.................................................-
0.5V to +7.0V
Commercial
0
°
C to +70
°
C
5V
±
10%
DC Voltage Applied to Outputs
in High Z State [1]
Industrial
–40
°
C to +85
°
C
5V
±
10%
....................................... -
0.5V to V CC + 0.5V
DC Input Voltage [1]
.................................... -
0.5V to V CC + 0.5V
Electrical Characteristics Over the Operating Range
CY62256
-
55
CY62256
-
70
Parameter
Description
Test Conditions
Min. Typ [2]
Max.
Min. Typ [2]
Max.
Unit
V OH
Output HIGH Voltage
V CC = Min., I OH =
-
1.0 mA 2.4
2.4
V
V OL
Output LOW Voltage
V CC = Min., I OL = 2.1 mA
0.4
0.4
V
V IH
Input HIGH Voltage
2.2
V CC
+0.5V
2.2
V CC
+0.5V
V
V IL
Input LOW Voltage
-
0.5
0.8
-
0.5
0.8
V
I IX
Input Load Current
GND < V I < V CC
-
0.5
+0.5
-
0.5
+0.5
m
A
I OZ
Output Leakage
Current
GND < V O < V CC , Output Dis-
abled
-
0.5
+0.5
-
0.5
+0.5
m
A
I CC
V CC Operating Supply
Current
V CC = Max.,
I OUT = 0 mA,
f = f MAX = 1/t RC
28
55
28
55
mA
L
25
50
25
50
mA
LL
25
50
25
50
mA
I SB1
Automatic CE
Power-Down Current—
TTL Inputs
Max. V CC , CE > V IH ,
V IN > V IH or
V IN < V IL , f = f MAX
0.5
2
0.5
2
mA
L
0.4
0.6
0.4
0.6
mA
LL
0.3
0.5
0.3
0.5
mA
I SB2
Automatic CE
Power-Down Current—
CMOS Inputs
Ma x. V CC ,
CE > V CC
1
5
1
5
mA
-
0.3V
L
2
50
2
50
m
A
0.3V
or V IN < 0.3V, f = 0
-
LL
0.1
5
0.1
5
m
A
Indust’l Temp Range LL
0.1
10
0.1
10
m
A
Shaded area contains preliminary information.
Capacitance [3]
Parameter
Description
Test Conditions
Max.
Unit
C IN
Input Capacitance
C, f = 1 MHz,
V CC = 5.0V
°
6
pF
C OUT
Output Capacitance
8
pF
2.0V for pulse durations of less than 20 ns.
2. Typical specifications are the mean values measured over a large sample size across normal production process variations and are taken at nominal conditions
(T A = 25
-
C, V CC ). Parameters are guaranteed by design and characterization, and not 100% tested.
3. Tested initially and after any design or process changes that may affect these parameters.
°
2
V IN > V CC
T A = 25
Note:
1. V IL (min.) =
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CY62256
AC Test Loads and Waveforms
R1 180 0 W
R1 1800 W
5V
OUTPUT
5V
OUTPUT
ALL INPUT PULSES
3.0V
90%
9 0 %
10%
10%
R2
990
R2
990
100 pF
5pF
GND
W
W
< 5ns
<5ns
INCLUDING
JIG AND
SCOPE
INCLUDING
JIG AND
SCOPE
C62256–5
C62256–6
(a)
(b)
Equivalent to:
THÉVENIN EQUIVALENT
639 W
OUTPUT
1.77V
Data Retention Characteristics
Parameter
Description
Conditions [4]
Min.
Typ. [2]
Max.
Unit
V DR
V CC for Data Retention
V CC = 3.0V,
CE > V CC
2.0
V
-
0.3V,
I CCDR
Data Retention Current
L
2
50
m
A
V IN > V CC
-
0.3V or
LL
V IN < 0.3V
0.1
5
m
A
LL Indust’l
0.1
10
m
A
t CDR [3]
Chip Deselect to Data
Retention Time
0
ns
t R [3]
Operation Recovery Time
t RC
ns
Data Retention Waveform
DATA RETENTION MODE
V CC
3.0V
t CDR
V DR > 2V
3.0V
t R
CE
C62256–7
Note:
4. No input may exceed V CC +0.5V.
3
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CY62256
Switching Characteristics Over the Operating Range [5]
CY62256
-
55
CY62256
70
Parameter
Description
Min.
Max.
Min.
Max.
Unit
READ CYCLE
t RC
Read Cycle Time
55
70
ns
t AA
Address to Data Valid
55
70
ns
t OHA
Data Hold from Address Change
5
5
ns
t ACE
CE LOW to Data Valid
55
70
ns
t DOE
OE LOW to Data Valid
25
35
ns
t LZOE
OE LOW to Low Z [6]
5
5
ns
t HZOE
OE HIGH to High Z [6, 7]
20
25
ns
t LZCE
CE LOW to Low Z [6]
5
5
ns
t HZCE
CE HIGH to High Z [6, 7]
20
25
ns
t PU
CE LOW to Power-Up
0
0
ns
t PD
CE HIGH to Power-Down
55
70
ns
WRITE CYCLE [8, 9]
t WC
Write Cycle Time
55
70
ns
t SCE
CE LOW to Write End
45
60
ns
t AW
Address Set-Up to Write End
45
60
ns
t HA
Address Hold from Write End
0
0
ns
t SA
Address Set-Up to Write Start
0
0
ns
t PWE
WE Pulse Width
40
50
ns
t SD
Data Set-Up to Write End
25
30
ns
t HD
Data Hold from Write End
0
0
ns
t HZWE
WE LOW to High Z [6, 7]
20
25
ns
t LZWE
WE HIGH to Low Z [6]
5
5
ns
Shaded area contains preliminary information.
Switching Waveforms
Read Cycle No. 1 [10,11]
t RC
ADDRESS
t OHA
t AA
DATA OUT
PREVIOUS DATA VALID
DATA VALID
C62256–8
Notes:
5. Test conditions assume signal transition time of 5 ns or less, timing reference levels of 1.5V, input pulse levels of 0 to 3.0V, and output loading of the specified
I OL /I OH and 100-pF load capacitance.
6. At any given temperature and voltage condition, t HZCE is less than t LZCE , t HZOE is less than t LZOE , and t HZWE is less than t LZWE for any given device.
7. t HZOE , t HZCE , and t HZWE are specified with C L = 5 pF as in part (b) of A C Te st Loads. Trans ition is measured ± 500 mV from steady-state voltage.
8. The internal write time of the memory is defined by the overlap of CE LOW and WE LOW. Both signals must be LOW to initiate a write and either signal can terminate
a write by going HIGH. The data input set-up and hold timi ng should b e re ferenced to the rising edge of the signal that terminates the write.
9. The minimum write cycle time for wr it e c ycle #3 (WE controlled, OE LOW) is the sum of t HZWE and t SD
10. Dev ice is continuously selected. OE, CE = V IL .
11. WE is HIGH for read cycle.
4
-
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CY62256
Switching Waveforms (continued)
Read Cycle No. 2 [11,12]
t RC
CE
t ACE
OE
t DOE
t HZOE
t HZCE
t LZOE
HIGH
DATA OUT
HIGH IMPEDANCE
DATA VALID
IMPEDAN CE
t LZCE
t PU
t PD
V CC
SUPPLY
CURRENT
ICC
50%
50%
ISB
C62256–9
Write Cycle No. 1 (WE Controlled)
[8,13,14]
t WC
ADDRESS
CE
t AW
t HA
WE
t SA
t PWE
OE
t SD
t HD
DATA I/O
NOTE
15
DATA IN VALID
t HZOE
C62256–10
Write Cycle No. 2 (CE Controlled)
[8,13,14]
t WC
ADDRES S
CE
t SCE
t SA
t AW
t HA
WE
t SD
t HD
DATA I/O
DATA IN VALID
C62256–11
Notes:
12. Address valid prior to or coinc ide nt with CE transition LOW.
13. D ata I/O is high impedance if OE = V IH .
14. If CE goes HIGH simultaneously with WE HIGH, the output remains in a high-impedance state.
5
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