m27v101 STMicroelectronics, m27v101 Datasheet - Page 9

• Manufacturer Part Number: m27v101
• Description: 1 Mbit 128kb X 8 Low Voltage Uv Eprom And Otp Eprom
• Manufacturer: STMicroelectronics

Electronic Signature
The Electronic Signature (ES) mode allows the
reading out of a binary code from an EPROM that
will identify its manufacturer and type. This mode
is intended for use by programming equipment to
automatically match the device to be programmed
with its corresponding programming algorithm.
The ES mode is functional in the 25°C ± 5°C am-
bient temperature range that is required when pro-
gramming the M27V101. To activate the ES mode,
the programming equipment must force 11.5V to
12.5V on address line A9 of the M27V101, with
V
sequenced from the device outputs by toggling ad-
dress line A0 from V
lines must be held at V
ture mode. Byte 0 (A0 = V
ufacturer code and byte 1 (A0 = V
identifier
M27V101, these two identifier bytes are given in
Table 4 and can be read-out on outputs Q7 to Q0.
Note that the M27V101 and M27C1001 have the
same identifier bytes.
PP
= V
CC
code.
= 5V. Two identifier bytes may then be
For
IL
IL
to V
the
during Electronic Signa-
IL
) represents the man-
IH
. All other address
STMicroelectronics
IH
) the device
ERASURE OPERATION (applies to UV EPROM)
The erasure characteristics of the M27V101 is
such that erasure begins when the cells are ex-
posed to light with wavelengths shorter than ap-
proximately 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 fluo-
rescent lighting could erase a typical M27V101 in
about 3 years, while it would take approximately 1
week to cause erasure when exposed to direct
sunlight. If the M27V101 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 M27V101 window to prevent unintentional era-
sure. The recommended erasure procedure for
the M27V101 is exposure to short wave ultraviolet
light which has a wavelength of 2537 Å. The inte-
grated dose (i.e. UV intensity x exposure time) for
erasure should be a minimum of 15 W-sec/cm
The erasure time with this dosage is approximate-
ly 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.
2
power rating. The M27V101
M27V101
9/15
2
.