M27V101 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
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M27V101 Datasheet PDF : 15 Pages
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M27V101
On-Board Programming
The M27V101 can be directly programmed in the
application circuit. See the relevant Application
Note AN620.
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
VPP=VCC=5V. Two identifier bytes may then be
sequenced from the device outputs by toggling ad-
dress line A0 from VIL to VIH. All other address
lines must be held at VIL during Electronic Signa-
ture mode.
Byte 0 (A0=VIL) represents the manufacturer code
and byte 1 (A0=VIH) the device identifier code. For
the STMicroelectronics M27V101, these two iden-
tifier bytes are given in Table 4 and can be read-
out on outputs Q0 to Q7. Note that the M27V101
and M27C1001 have the same identifier bytes.
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/cm2.
The erasure time with this dosage is approximate-
ly 15 to 20 minutes using an ultraviolet lamp with
12000 µW/cm2 power rating. The M27V101
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.
9/15
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