m27w101 STMicroelectronics, m27w101 Datasheet - Page 11

• Manufacturer Part Number: m27w101
• Description: 1 Mbit 128kb X8 Low Voltage Uv Eprom And Otp Eprom
• Manufacturer: STMicroelectronics

M27W101
2.10
Byte 0 (A0 = V
identifier code. For the STMicroelectronics M27W101, these two identifier bytes are given in
Table
Note that the M27W101 and M27C1001 have the same identifier byte.
Table 3.
Erasure operation (applies to UV EPROM)
The erasure characteristics of the M27W101 is such that erasure begins when the cells are
exposed to light with wavelengths shorter than approximately 4000 Å. It should be noted
that sunlight and some type of fluorescent lamps have wavelengths in the 3000-4000 Å
range. Research shows that constant exposure to room level fluorescent lighting could
erase a typical M27W101 in about 3 years, while it would take approximately 1 week to
cause erasure when exposed to direct sunlight. If the M27W101 is to be exposed to these
types of lighting conditions for extended periods of time, it is suggested that opaque labels
be put over the M27W101 window to prevent unintentional erasure. The recommended
erasure procedure for the M27W101 is exposure to short wave ultraviolet light which has a
wavelength of 2537 Å. The integrated dose (i.e. UV intensity x exposure time) for erasure
should be a minimum of 15 W-sec/cm
15 to 20 minutes using an ultraviolet lamp with 12000 µW/cm
should be placed within 2.5 cm (1 inch) of the lamp tubes during the erasure. Some lamps
have a filter on their tubes which should be removed before erasure.
Manufacturer’s Code
Device Code
Table 3
Identifier
Electronic Signature
and can be read-out on outputs Q7 to Q0.
IL
) represents the manufacturer code and byte 1 (A0 = V
V
V
A0
IH
IL
Q7
0
0
2
Q6
. The erasure time with this dosage is approximately
0
0
Q5
1
0
Q4
0
0
Q3
0
0
2
power rating. The M27W101
Q2
0
1
Q1
IH
0
0
Device description
) the device
Q0
0
1
Hex Data
20h
05h
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