M27V160-100B1TR 데이터 시트보기 (PDF) - STMicroelectronics
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M27V160-100B1TR Datasheet PDF : 15 Pages
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M27V160
On-Board Programming
The M27V160 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 M27V160. To activate the ES mode,
the programming equipment must force 11.5V to
12.5V on address line A9 of the M27V160, with
VPP = VCC = 5V.
Two identifier bytes may then be sequenced from
the device outputs by toggling address line A0
from VIL to VIH. All other address lines must be
held at VIL during Electronic Signature mode.
Byte 0 (A0 = VIL) represents the manufacturer
code and byte 1 (A0 = VIH) the device identifier
code. For the STMicroelectronics M27V160, these
two identifier bytes are given in Table 4 and can be
read-out on outputs Q7 to Q0. Note that the
M27V160 and M27C160 have the same identifier
bytes.
ERASURE OPERATION (applies to UV EPROM)
The erasure characteristics of the M27V160 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 M27V160 in
about 3 years, while it would take approximately 1
week to cause erasure when exposed to direct
sunlight. If the M27V160 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 M27V160 window to prevent unintentional era-
sure. The recommended erasure procedure for
M27V160 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 30 W-sec/cm2.
The erasure time with this dosage is approximate-
ly 30 to 40 minutes using an ultraviolet lamp with
12000 µW/cm2 power rating. The M27V160
should be placed within 2.5cm (1 inch) of the lamp
tubes during the erasure. Some lamps have a filter
on their tubes which should be removed before
erasure.
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