Cypress CY7C293A, CY7C291A, CY7C292A manual Erasure Characteristics, Programming Information

CY7C291A

CY7C292A/CY7C293A

Switching Characteristics Over the Operating Range[3, 4]

				7C291A-25		7C291A-35		7C291A-50
				7C292A-25		7C292A-35		7C292A-50
				7C293A-25		7C293A-35		7C293A-50
		7C291A-20		7C291AL-25		7C291AL-35		7C291AL-50
		7C292A-20		7C292AL-25		7C292AL-35		7C292AL-50
		7C293A-20		7C293AL-25		7C293AL-35		7C293AL-50
Parameter	Description	Min.	Max.	Min.	Max.	Min.	Max.	Min.	Max.	Unit

Notes:

6.tHZCS2 and tACS2 refer to 7C293A CS1 only.

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 with a 12 mW/cm2 power rating, the exposure time would be approximately 35 minutes.

Table 1. Mode Selection

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. 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 located at the end of this section. Programming algorithms can be ob- tained from any Cypress representative.

Pin Function[7]

Read or Output Disable

A10 −

A0

CS3

CS2

CS1

O7 −

O0

Mode

Other

A10 −

A0

PGM

VFY

VPP

D7 −

D0

Read

A10 −

A0

VIH

VIH

VIL

O7

−

O0

Output Disable[8]

A

10

−

A

X

X

V

IH

High Z

0

Output Disable

A10 −

A0

X

VIL

X

High Z

Output Disable

A10 −

A0

VIL

X

X

High Z

Program

A10 −

A0

VILP

VIHP

VPP

D7

−

D0

Program Verify

A10 −

A0

VIHP

VILP

VPP

O7

−

O0

Program Inhibit

A10 −

A0

VIHP

VIHP

VPP

High Z

Intelligent Program

A10

−

A0

VILP

VIHP

VPP

D7

−

D0

Blank Check Zeros

A10

−

A0

VIHP

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.

6