fax id: 3026
CY27C256A
1-Megabit (32K x 8) CMOS EPROM
Features
•
•
•
•
•
•
Very fast read access time: (45−200 ns)
5V ± 10% power supply
Capable of withstanding >2001V ESD
Latch-up protection up to 200 mA
Two line control functions to prevent bus contention
Standard JEDEC packages
— 32-pin PLCC
— 28-pin TSOP
— 28-pin, 600-mil plastic DIP
— 32-pin, hermetic LCC
— 28-pin, 600-mil hermetic DIP
• Available in commercial, industrial, and military
temperature ranges
windowed packages (28-pin hermetic DIP and 32-pin LCC)
which allow the device to be erased with UV light for 100%
reprogrammability.
The CY27C256A is equipped with a power-down chip enable
(CE) input and output enable (OE) to prevent bus contention.
When CE is deasserted, the device powers down to a
low-power stand-by mode. The OE pin three-states the out-
puts without putting the device into stand-by mode. While CE
offers lower power, OE provides a more rapid transition to and
from three-stated outputs.
The memory cells utilize proven EPROM floating-gate
technology and byte-wide intelligent programming algorithms.
The EPROM cell requires only 12.75V for the supervoltage
and low programming current allows for gang programming.
The device allows for each memory location to be tested
100%, because each location is written to, erased, and
repeatedly exercised prior to encapsulation. Each device is
also tested for AC performance to guarantee that the product
will meet DC and AC specification limits after customer
programming.
The CY27C256A is read by asserting both the CE and the OE
inputs. The contents of the memory location selected by the
address on inputs A
14
–A
0
will appear at the outputs O
7
−O
0
.
Functional Description
The CY27C256A is a high-performance, 256-Kbit ultraviolet
erasable programmable read-only memory (EPROM) orga-
nized as 32 Kbytes by 8 bits. It is available in JEDEC-standard,
one-time programmable (OTP), 32-pin PLCC and 28-pin PDIP
and TSOP packages. The CY27C256A is also available in
Logic Block Diagram
A0
A1
A2
A3
A4
A5
A6
PROGRAMMABLE
ARRAY
O0
O1
O2
MULTIPLEXER
O3
ADDRESS INPUTS
A7
A8
A9
A10
A11
A12
A13
A14
DATA OUTPUTS
O4
O5
ADDRESS
DECODER
POWER DOWN
O6
O7
CE
OE
OUTPUT ENABLE
DECODER
C256A–1
Cypress Semiconductor Corporation
•
3901 North First Street
•
San Jose •
CA 95134 •
408-943-2600
April 1995 - Revised November 10, 1997
CY27C256A
Pin Configurations
TSOP (Z)
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
21
20
19
18
17
16
15
14
13
12
11
10
9
8
PLCC/LCC (J and Q)
Top View
A7
A12
VPP
DU
VCC
A14
A13
[1]
DIP/WDIP (P and W)
Top View
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
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
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
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
A
6
A
5
A
4
A
3
A
2
A
1
A
0
NC
O
0
4 3 2 1 32 31 30
29
5
28
6
27
7
26
8
25
9
24
10
23
11
22
12
21
13
14 15 16 17 18 19 20
O1
O2
GND
DU
O3
O4
O5
A
8
A
9
A
11
NC
OE
A
10
CE
O
7
O
6
C256A–2
C256A–3
C256A–4
Selection Guide
–45
Maximum Access Time (ns)
CE Access Time (ns)
OE Access Time (ns)
I
CC[2]
(mA)
Power Supply Current
I
SB[3]
(mA)
Stand-by Current
Com’l(Max)
Mil
Com’l(Max)
Mil
45
45
18
45
55
15
25
–55
55
55
20
45
55
15
25
–70
70
70
25
45
55
15
25
–90
90
90
30
45
55
15
25
–120
120
120
30
45
55
15
25
–150
150
150
40
45
55
15
25
–200
200
200
40
45
55
15
25
Maximum Ratings
(Above which the useful life may be impaired. For user
guidelines, 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 +5.5V
DC Input Voltage............................................ –3.0V to +7.0V
Transient Input Voltage ................................–3.0V for <20 ns
DC Program Voltage ....................................................13.0 V
UV Erasure ...................................................7258 Wsec/cm
2
Static Discharge Voltage............................................>2001V
(per MIL-STD-883, Method 3015)
Latch-Up Current .....................................................>200 mA
Operating Range
Range
Commercial
Industrial
[4]
Military
[5]
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%
Notes:
1. For LCC/PLCC only: Pins 1 and 17 are designated as DU (DON’T USE)
and should not be used.
2. V
CC
= Max., I
OUT
= 0 mA, f=5 MHz.
3. V
CC
= Max., CE = V
IH
.
4. Contact a Cypress representative for industrial temperature range
specification.
5. T
A
is the “instant on” case temperature.
2
CY27C256A
DC Electrical Characteristics
Over the Operating Range
[6,7]
Parameter
V
OH
V
OL
V
IH
V
IL
I
LI
I
LO
I
CC
Description
Output HIGH Voltage
Output LOW Voltage
Input HIGH Level
Input LOW Level
Input Leakage Current
Output Leakage Current
Power Supply Current
Test Conditions
V
CC
= Min., I
OH
= –400
µA
V
CC
= Min., I
OL
= 2 mA
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 Disable
V
CC
=Max., I
OUT
=0 mA,
f=5 MHz
V
CC
=Max.,CE = V
IH
Com’l
Mil
Com’l
Mil
–10
–10
2.0
Min.
2.4
0.45
V
CC
+0.5
0.8
+10
+10
45
55
15
25
Max.
Unit
V
V
V
V
µA
µA
mA
mA
mA
mA
I
SB
Stand-By Current
Capacitance
[8]
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
12
Unit
pF
pF
Notes:
6. See the last page of this specification for Group A subgroup testing information.
7. See Introduction to CMOS NVMs in this Data Book for general information on testing.
8. This parameter is sampled only and is not 100% tested.
AC Test Loads and Waveforms
R1 1867Ω
5V
OUTPUT
R2
1339Ω
2.4V
0.40V
2.0V
0.8V
TEST POINTS
2.0V
0.8V
< 20 ns
INPUT
OUTPUT
For
−70, −90,
120, 150,
−200
DEVICES ONLY
C
L
C
L
INCLUDES
JIG AND SCOPE
< 20 ns
INPUTS ARE DRIVEN AT 2.4V FOR A
LOGIC 1 AND 0.40V FOR A LOGIC 0.
THEVENIN EQUIVALENT
780Ω
OUTPUT
C
L
2.088V
3.0V
1.5V
GND
< 5 ns
For
−45
and
−55
DEVICES ONLY
TEST POINTS
1.5V
< 5 ns
Notes: C
L
= 30 pF for –45 and –55 devices
C
L
= 100 pF for –70, –90, –120, –150, and –200 devices
C
L
= 5 pF for t
DF
C256A–5
INPUT
OUTPUT
C256A–6
INPUTS ARE DRIVEN AT 3.0V FOR A
LOGIC 1 AND 0.0V FOR A LOGIC 0.
3
CY27C256A
Switching Characteristics
Over the Operating Range
−45
Parameter
t
ACC
t
HZOE
t
OE
t
DF[8]
Description
Address to
Output Valid
Output Enable In-
active to High Z
OE Active to
Output Valid
OE or CE Inactive
to High Z, which-
ever occurs first
CE Active to
Output Valid
Output Data Hold
0
Min
−55
−70
−90
−120
−150
−200
Max Min Max Min Max Min Max Min Max Min Max Min Max Unit
45
20
18
25
55
20
20
25
70
25
25
25
90
25
30
30
120
30
30
30
150
30
40
30
200
30
40
30
ns
ns
ns
ns
t
CE
t
OH
45
0
55
0
70
0
90
0
120
0
150
0
200
ns
ns
Switching Waveform
CE
OE
A
0
−
A
15
ADDRA
t
ACC
t
CE
ADDRB
t
ACC
t
HZOE
t
OH
t
OE
t
DF
DATAB
C256A–7
O
0
−
O
7
DATA A
DATA B
Erasure Characteristics
Wavelengths of light less than 4000 Angstroms begin to erase
the CY27C256A in the windowed package. For this reason, an
opaque label should be placed over the window if the EPROM
is exposed to sunlight or fluorescent lighting for extended
periods of time.
The recommended dose of ultraviolet light for erasure is a
wavelength of 2537 Angstroms for a minimum dose (UV
intensity multiplied by exposure time) of 15 Wsec/cm
2
. For an
ultraviolet lamp with a 12 mW/cm
2
power rating, the exposure
time would be approximately 15 minutes. The CY27C256A
needs to be 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 recommended 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
packages, please see the PROM Programming Information
located at the end of this section. Programming algorithms can
be obtained from any Cypress representative.
4
CY27C256A
Table 1. Programming Electrical Characteristics
Parameter
V
PP
I
PP
V
IHP
V
ILP
V
CCP
Table 2. Mode Selection
Pin Function
[9]
Mode
Read
Output Disable
Stand-by(TTL)
Program
Program Verify
Program Inhibit
Signature Read (MFG)
[11]
Signature Read (DEV)
[11]
Notes:
9. X can be V
IL
or V
IH
10. V
HV
=12V±0.5V
11. A
1
−
A
8
and A
10
−
A
14
= V
IL
Description
Programming Power Supply
Programming Supply Current
Programming Input Voltage HIGH
Programming Input Voltage LOW
Programming V
CC
Min.
12.5
Max.
13
50
Unit
V
mA
V
V
V
3.0
–0.5
6.0
V
CC
0.4
6.5
CE
V
IL
V
IL
V
IH
V
ILP
V
IHP
V
IHP
V
IL
V
IL
OE
V
IL
V
IH
X
V
IHP
V
ILP
V
IHP
V
IL
V
IL
V
PP
V
CC
V
CC
V
CC
V
PP
V
PP
V
PP
V
CC
V
CC
A
0
A
0
X
X
A
0
A
0
X
V
IL
V
IH
A
9
A
9
X
X
A
9
A
9
X
V
HV[10]
V
HV[10]
Outputs
Dout
High Z
High Z
Din
Dout
High Z
34H
1FH
5
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