Cypress Semiconductor CY7C291A Технический паспорт - Страница 6
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Switching Characteristics
Parameter
Notes:
6.
t
and t
refer to 7C293A CS
HZCS2
ACS2
Erasure Characteristics
Wavelengths of light less than 4000 Angstroms begin to erase
these PROMs. 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 inten-
sity x exposure time) of 25 Wsec/cm2. For an ultraviolet lamp
2
with a 12 mW/cm
power rating, the exposure time would be
approximately 35 minutes.
Table 1. Mode Selection
Read or Output Disable
Mode
Other
Read
[8]
Output Disable
Output Disable
Output Disable
Program
Program Verify
Program Inhibit
Intelligent Program
Blank Check Zeros
Notes:
7.
X = "don't care" but not to exceed V
8.
The power-down mode for the CY7C293A is activated by deselecting CS
Over the Operating Range
Description
Min.
only.
1
A
A
10
0
A
A
10
0
A
A
10
0
A
A
10
0
A
A
10
0
A
A
10
0
A
A
10
0
A
A
10
0
A
A
10
0
A
A
10
0
A
A
10
0
+5%.
CC
[3, 4]
7C291A-25
7C292A-25
7C293A-25
7C291A-20
7C291AL-25
7C292A-20
7C292AL-25
7C293A-20
7C293AL-25
Max.
Min.
Max.
These PROMs need to be within 1 inch of the lamp during
erasure. Permanent damage may result if the PROM is ex-
posed to high-intensity UV light for an extended period of time.
2
7258 Wsec/cm
is the recommended maximum dosage.
Programming Information
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 PROM Programming Information located
at the end of this section. Programming algorithms can be ob-
tained from any Cypress representative.
Pin Function
CS
CS
3
PGM
VFY
V
V
IH
X
X
V
V
IL
V
V
ILP
V
V
IHP
V
V
IHP
V
V
ILP
V
V
IHP
.
1
6
CY7C291A
CY7C292A/CY7C293A
7C291A-35
7C291A-50
7C292A-35
7C292A-50
7C293A-35
7C293A-50
7C291AL-35
7C291AL-50
7C292AL-35
7C292AL-50
7C293AL-35
7C293AL-50
Min.
Max.
Min.
[7]
CS
2
1
V
PP
V
IH
IL
X
V
IH
X
IL
X
X
V
IHP
PP
V
ILP
PP
V
IHP
PP
V
IHP
PP
V
ILP
PP
Max.
Unit
O
O
7
0
D
D
7
0
O
O
7
0
High Z
High Z
High Z
D
D
7
0
O
O
7
0
High Z
D
D
7
0
Zeros