1CY 27C2 56
fax id: 3013
CY27C256
32K x 8-Bit CMOS EPROM
Features
• Wide speed range
— 45 ns to 200 ns (commercial and military)
• Low power
— 248 mW (commercial)
— 303 mW (military)
• Low standby power
— Less than 83 mW when deselected
•
±10%
Power supply tolerance
able in a CerDIP package equipped with an erasure window
to provide for reprogrammability. When exposed to UV light,
the EPROM is erased and can be reprogrammed. The mem-
ory cells utilize proven EPROM floating gate technology and
byte-wide intelligent programming algorithms.
The CY27C256 offers the advantage of lower power and su-
perior performance and programming yield. The EPROM cell
requires only 12.5V for the super voltage, and low current re-
quirements allow for gang programming. The EPROM cells
allow each memory location to be tested 100% because each
location is written into, erased, and repeatedly exercised prior
to encapsulation. Each EPROM is also tested for AC perfor-
mance to guarantee that after customer programming, the
product will meet both DC and AC specification limits.
Reading the CY27C256 is accomplished by placing active
LOW signals on OE and CE. The contents of the memory location
addressed by the address lines (A
0
- A
14
) will become available on
the output lines (O
0
- O
7
).
Functional Description
The CY27C256 is a high-performance 32,768-word by 8-bit
CMOS EPROM. When disabled (CE HIGH), the CY27C256
automatically powers down into a low-power stand-by mode.
The CY27C256 is packaged in the industry standard 600-mil
DIP, PLCC, and TSOP packages. The CY27C256 is also avail-
Logic Block Diagram
A
14
A
13
A
12
A
11
A
10
A
9
A
8
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
POWER–DOWN
O
1
COLUMN
ADDRESS
O
2
O
3
ADDRESS
DECODER
O
4
ROW
ADDRESS
256 x 1024
PROGRAMABLE
ARRAY
8 x 1 OF 128
MULTIPLEXER
O
7
Pin Configurations
DIP/Flatpack
O
6
V
PP
A
12
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
O
0
O
1
O
2
GND
1
28
2
27
3
26
4
25
5
24
6 27C256 23
22
7
8
21
9
20
10
19
11
18
12
17
13
16
14
15
V
CC
A
14
A
13
A
8
A
9
A
11
OE
A
10
CE
O
7
O
6
O
5
O
4
O
3
27c256–2
LCC/PLCC
[1]
4 3 2 1 32 31 30
29
5
28
27C256
6
27
7
26
8
25
9
24
10
23
11
22
12
21
13
14151617 181920
O
5
A
6
A
5
A
4
A
3
A
2
A
1
A
0
NC
O
0
A
8
A
9
A
11
NC
OE
A
10
CE
O
7
O
6
27c256–3
O
0
CE
27c256–1
OE
Note:
1. For PLCC only: Pins 1 and 17 are common and tied to the die attach pad. They must therefore be DU (don’t use) for the PLCC package.
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose
•
CA 95134 •
408-943-2600
May 1993 – Revised August 1994
CY27C256
Selection Guide
27C256-45 27C256-55
Maximum Access Time (ns)
Maximum
Operating
Current (mA)
Standby Current
(mA)
Com’l
Mil
Com’l
Mil
45
45
55
15
20
45
15
55
45
55
15
20
55
20
27C256-70
70
45
55
15
20
70
25
27C256-90 27C256-120 27C256-150 27C256-200
90
45
55
15
20
90
30
120
45
55
15
20
120
30
150
45
55
15
20
150
40
200
45
55
15
20
200
40
Chip Select Time (ns)
Output Enable Time (ns)
Pin Configurations
28-Pin TSOP
Top View
OE
A
11
A
9
A
8
A
13
A
14
V
CC
V
PP
A
12
A
7
A
6
A
5
A
4
A
3
22
23
24
25
26
27
28
1
2
3
4
5
6
7
27C256T
21
20
19
18
17
16
15
14
13
12
11
10
9
8
A
10
CE
O
7
O
6
O
5
O
4
O
3
GND
O
2
O
1
O
0
A
0
A
1
A
2
27c256–4
32-Pin TSOP
T
op View
OE
1
A
19
A
8
A
3
A
1
NC
4
A
1
V
CC
P
V
P
NC
2
A
1
7
A
6
A
5
A
4
A
3
A
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
27C256
NC
A
10
CE
O
7
O
6
O
5
O
4
O
3
GND
O
2
O
1
O
0
NC
A
0
A
1
A
2
27c256–5
Maximum Ratings
(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............................................. -55
°
C to +125
°
C
Supply Voltage to Ground Potential ................-0.5V to +7.0V
DC Voltage Applied to Outputs
in High Z State................................................ -0.5V to +7.0V
DC Input Voltage .............................................-3.0V to +7.0V
DC Program Voltage .................................................... 13.0V
Static Discharge Voltage ........................................... >2001V
(per MIL-STD-883, Method 3015)
Latch-Up Current ..................................................... >200 mA
UV Exposure ................................................ 7258 Wsec/cm
2
2
CY27C256
Operating Range
Range
Commercial
Industrial
[2]
Military
[3]
Ambient
Temperature
0
°
C to +70
°
C
-40
°
C to +85
°
C
-55
°
C to +125
°
C
V
CC
5V
±10%
5V
±10%
5V
±10%
Electrical Characteristics
Over the Operating Range
[4]
27C256-45, 55, 70, 90,
120, 150, 200
Parameter
V
OH
V
OL
V
IH
V
IL
I
IX
I
OZ
I
OS
I
CC
Description
Output HIGH Voltage
Output LOW Voltage
Input HIGH Level
Input LOW Level
Input Current
Output Leakage Current
Output Short Circuit Current
[6]
Power Supply Current
Test Conditions
V
CC
= Min., I
OH
= –4.0 mA
V
CC
= Min., I
OL
= 16.0 mA
[5]
Guaranteed Input Logical HIGH Voltage for All
Inputs
Guaranteed Input Logical LOW Voltage for All
Inputs
GND < V
IN
< V
CC
GND < V
OUT
< V
CC
,
Output Disabled
V
CC
= Max., V
OUT
= GND
V
CC
= Max., V
IN
=V
IH
,
I
OUT
= 0 mA, CE=V
IL
,
OE = V
IH
V
CC
= Max., CE = V
IH
Commercial
Military
Commercial
Military
Commercial
Military
V
PP
I
PP
V
IHP
V
ILP
Programming Supply Voltage
Programming Supply Current
Input HIGH Programming
Voltage
Input LOW Programming
Voltage
3.0
0.4
12
2.0
–0.3
–10
–10
–40
–20
Min.
2.4
0.4
V
CC
0.8
+10
+10
+40
–90
45
55
15
20
13
50
V
mA
V
V
mA
mA
mA
Max.
Unit
V
V
V
V
µA
µA
I
SB
Standby Supply Current
Capacitance
[7]
Parameter
C
IN
C
OUT
Description
Input Capacitance
Output Capacitance
Test Conditions
T
A
= 25
°
C, f = 1 MHz,
V
CC
= 5.0V
Max.
10
10
Unit
pF
pF
Notes:
2. Contact a Cypress representative for information on industrial temperature range specifications.
3. T
A
is the “instant on” case temperature.
4. See the last page of this specification for Group A subgroup testing information.
5. I
OL
=12.0 mA for military devices.
6. For test purposes, not more than one output at a time should be shorted. Short circuit test duration should not exceed 30 seconds.
7. See Introduction to CMOS PROMs in this Data Book for general information on testing.
3
CY27C256
AC Test Loads and Waveforms
R1 250Ω (329Ω MIL)
5V
OUTPUT
30 pF
INCLUDING
JIG AND
SCOPE
R2 167Ω
(202Ω MIL)
5V
OUTPUT
5 pF
INCLUDING
JIG AND
SCOPE
R2 167Ω
(202Ω MIL)
GND
≤
5 ns
R1 250Ω (329Ω MIL)
3.0V
ALL INPUT PULSES
90%
10%
90%
10%
≤
5 ns
27c256–6
27c256–7
(a) Normal Load
(b) High Z Load
Equivalent to:
OUTPUT
THÉVENIN EQUIVALENT
100Ω
Commercial
2.00V
OUTPUT
125Ω
Military
1.9V
Switching Characteristics
Over the Operating Range
[4,7 ]
27C256-45
Parameter
t
AA
t
HZOE
t
OE
t
HZCE
t
ACE
t
PU
t
PD
t
OH
Description
Address to Output Valid
Outpout Enable Inactive to High Z
Output Enable Active to Output Valid
Chip Enable Inactive to High Z
Chip Enable Active to Output Valid
Chip Enable Active to Power Up
Chip Enable Inactive to Power Down
Output Hold from Address Change
0
0
45
0
Min.
Max.
45
15
15
20
45
0
55
0
27C256-55
Min.
Max.
55
20
20
25
55
0
70
0
27C256-70
Min.
Max.
70
25
25
25
70
0
90
27C256-90
Min.
Max.
90
25
30
25
90
Unit
ns
ns
ns
ns
ns
ns
ns
ns
Switching Characteristics
Over the Operating Range
[4, 7]
27C256-120
Parameter
t
AA
t
HZOE
t
OE
t
HZCE
t
ACE
t
PU
t
PD
t
OH
Description
Address to Output Valid
Outpout Enable Inactive to High Z
Output Enable Active to Output Valid
Chip Enable Inactive to High Z
Chip Enable Active to Output Valid
Chip Enable Active to Power Up
Chip Enable Inactive to Power Down
Output Hold from Address Change
0
0
120
0
Min.
Max.
120
30
30
30
120
0
150
0
27C256-150
Min.
Max.
150
30
40
30
150
0
200
27C256-200
Min.
Max.
200
30
40
30
200
Unit
ns
ns
ns
ns
ns
ns
ns
ns
4
CY27C256
Switching Waveform
t
PD
I
CC
SUPPLY
CURRENT
A
0
- A
14
ADDRESS
50%
t
PU
POWER–DOWN CONTROLLED BY CE
50%
OE, CE
t
AA
t
OH
O
0
- O
7
PREVIOUS DATA VALID
(t
HZOE
)
t
HZCE
DATA VALID
(t
OE
)
t
ACE
HIGH Z
27c256–8
Erasure Characteristics
Wavelengths of light less than 4000 Å begin to erase the
27C256 in the windowed package. For this reason, an opaque
label should be placed over the window if the EPROM is ex-
posed to sunlight or fluorescent lighting for extended periods
of time.
The recommended dose of ultraviolet light for erasure is a
wavelength of 2537 Å for a minimum dose (UV intensity mul-
tiplied by exposure time) of 25 Wsec/cm2. For an ultraviolet
lamp with a 12 mW/cm
2
power rating, the exposure time would
be approximately 35 minutes. The CY27C256 needs to be
Table 1. CY27C256 Mode Selection.
Mode
A
14
-A
0
Read
Output Disable
Power Down
A
14
-A
0
A
14
-A
0
A
14
-A
0
OE
V
IL
V
IH
X
within 1 inch of the lamp during erasure. Permanent damage
may result if the EPROM is exposed to high-intensity UV light
for an extended period of time. 7258 Wsec/cm
2
is the recom-
mended maximum dosage.
Programming Modes
Programming support is available from Cypress as well as
from a number of third-party software vendors. For detailed
programming information, including a listing of software pack-
ages, please see the EPROM Programming Information locat-
ed at the end of this section. Programming algorithms can be
obtained from any Cypress representative.
Pin Function
[8]
CE
V
IL
V
IL
V
IH
V
PP
X
[9]
X
X
O
7
-O
0
O
7
-O
0
High Z
High Z
Notes:
8. X can be V
IL
or V
IH
9. V
PP
should not exceed V
CC
in read mode.
5
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