CY7C271-45WMB Cypress Semiconductor Corp, CY7C271-45WMB Datasheet - Page 4

• Manufacturer Part Number: CY7C271-45WMB
• Manufacturer: Cypress Semiconductor Corp

Specifications of CY7C271-45WMB

• Density: 256Kb
• Organization: 32Kx8
• Interface Type: Parallel
• In System Programmable: In System/External
• Access Time (max): 45ns
• Package Type: Windowed CDIP
• Reprogramming Technique: UV
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (min): 4.5V
• Operating Supply Voltage (max): 5.5V
• Supply Current: 130mA
• Pin Count: 28
• Mounting: Through Hole
• Operating Temp Range: -55C to 125C
• Operating Temperature Classification: Military
• Lead Free Status / RoHS Status: Not Compliant

Document #: 38-04008 Rev. *C
Switching Characteristics
Switching Waveform
Erasure Characteristics
Wavelengths of light less than 4000 angstroms begin to erase
the CY7C271 and CY7C274 in the windowed package. For
this reason, an opaque label should be placed over the window
if the PROM 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 × exposure time) of 25 Wsec/cm
with a 12 mW/cm
imately 35 minutes. The CY7C271 or CY7C274 needs to be within 1
inch of the lamp during erasure. Permanent damage may result if the
OE, CE, CS
Note
t
t
t
t
t
t
t
t
t
t
Parameter
7. CS
AA
HZCS
ACS
HZOE
OE
HZCE
ACE
PU
PD
OH
CURRENT
ADDRESS
A
O
SUPPLY
2
0
and CS
0
− A
- O
CS
V
1
CC
[7]
14
2
7
1
are used on the 7C271 only. OE is used on the 7C274 only.
Address to Output Valid
Chip Select Inactive to High Z (CS
7C271 Only)
Chip Select Active to Output Valid (CS
7C271 Only)
Output Enable Inactive to High Z (OE, 7C274
Only)
Output Enable Active to Output Valid (OE, 7C274
Only)
Chip Enable Inactive to High Z (CE Only)
Chip Enable Active to Output Valid (CE Only)
Chip Enable Active to Power Up
Chip Enable Inactive to Power Down
Output Hold from Address Change
2
PREVIOUS DA TA VALID
power rating, the exposure time would be approx-
Description
t
Over the Operating Range
OH
t
2
AA
. For an ultraviolet lamp
1
and CS
1
DATA VALID
and CS
2
t
,
PD
t
(t
HZCS(E)
2
HZOE
[3,6]
,
Min. Max. Min. Max. Min. Max. Min. Max.
)
PROM is exposed to high-intensity UV light for an extended period of
time. 7258 Wsec/cm
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.
7C274-30
0
0
50%
30
20
20
20
20
35
35
35
7C271-35
7C274-35
0
0
t
PU
HIGH Z
2
is the recommended maximum dosage.
t
50%
35
25
25
20
20
40
40
40
ACS(E)
(t
POWER-DOWN CONTROLLED BY CE
OE
)
7C271-45
7C274-45
0
0
45
30
30
25
25
50
50
50
7C271-55
0
0
CY7C271
CY7C274
Page 4 of 13
55
30
30
25
25
60
60
60
Unit
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
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