CY27H512
PRELIMINARY
5
Erasure Characteristics
Wavelengths of light less than 4000 Angstroms begin to erase the
CY27H512 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 wave
length of 2537 Angstroms for a minimum dose (UV intensity mul
tiplied by exposure time) of 25 Wsec/cm2. For an ultraviolet lamp
with a 12 mW/cm2 power rating, the exposure time would be ap
proximately 35 minutes. The CY27H512 needs to be within 1 inch
of the lamp during erasure. Permanent damage may result if the
EPROM is exposed to highintensity UV light for an extended pe
riod of time. 7258 Wsec/cm2 is the recommended maximum
dosage.
Programming Modes
Programming support is available from Cypress as well as from a
number of thirdparty software vendors. For detailed program
ming 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.
Table 1. Programming Electrical Characteristics
Parameter
Description
Min.
Max.
Unit
VPP
Programming Power Supply
12.5
13
V
IPP
Programming Supply Current
50
mA
VIHP
Programming Input Voltage HIGH
3.0
VCC
V
VILP
Programming Input Voltage LOW
-0.5
0.4
V
VCCP
Programming VCC
6.0
6.5
V
Table 2. Mode Selection
Pin Function[8]
Mode
CE
OE/VPP
A0
A9
Data
Read
VIL
VIL
A0
A9
O7 - O0
Output Disable
X
VIH
A0
A9
High Z
Standby
VIH
X
X
X
High Z
Program
VILP
VPP
A0
A9
D7 - D0
Program Verify
VILP
VILP
A0
A9
O7 - O0
Program Inhibit
VIHP
VPP
A0
A9
High Z
Signature Read (MFG)
VIL
VIL
VIL
VHV[9]
34H
Signature Read (DEV)
VIL
VIL
VIH
VHV[9]
1FH
Note:
8. X can be VIL or VIH.
9. VHV=12±0.5V
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