CY7C291A
CY7C292A/CY7C293A
6
Erasure Characteristics
Wavelengths of light less than 4000 Angstroms begin to er ase
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
with a 12 mW/cm2 power rating, the exposure time would be
approximately 35 minutes.
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 ti me.
7258 Wsec/cm2 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 loc ated
at the end of this section. Programming algorithms can be ob-
tained from any Cypress representative.
Notes:
6. tHZCS2 and tACS2 refer to 7C293A CS1 only.
Switching Characteristics Over the Operating Range[3, 4]
7C291A-20
7C292A-20
7C293A-20
7C291A-25
7C292A-25
7C293A-25
7C291AL-25
7C292AL-25
7C293AL-25
7C291A-35
7C292A-35
7C293A-35
7C291AL-35
7C292AL-35
7C293AL-35
7C291A-50
7C292A-50
7C293A-50
7C291AL-50
7C292AL-50
7C293AL-50
Paramete r Description Min. Max. Min. Max. Min. Max. Min. Max. Unit
Table 1. Mode Selection
Pin Function[7]
Read or Output Disable A10 − A0CS3CS2CS1O7 − O0
Mode Other A10 − A0PGM VFY VPP D7 − D0
Read A10 − A0VIH VIH VIL O7 − O0
Output Disable[8] A10 − A0X X VIH High Z
Output Disable A10 − A0X VIL XHigh Z
Output Disable A10 − A0VIL X X High Z
Program A10 − A0VILP VIHP VPP D7 − D0
Program Verify A10 − A0VIHP VILP VPP O7 − O0
Program Inhibit A10 − A0VIHP VIHP VPP High Z
Intelligent Program A10 − A0VILP VIHP VPP D7 − D0
Blank Check Zeros A10 − A0VIHP VILP VPP Zeros
Notes:
7. X = “don’t care” but not to exceed VCC +5%.
8. The power-down mode for the CY7C293A is activated by deselecting CS1.