M27V160-100M1 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
M27V160-100M1 Datasheet PDF : 25 Pages
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M27V160
Device description
2.9
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
ambient temperature range that is required when programming 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 3 and can be read-out on outputs Q7 to Q0. Note that the M27V160 and M27C160
have the same identifier bytes.
Table 3. Electronic Signature
Identifier
Q15 Q14 Q13 Q12 Q11 Q10 Q9 Q8
A0 and and and and and and and and
Q7 Q6 Q5 Q4 Q3 Q2 Q1 Q0
Manufacturer’s Code VIL 0
0
1
0
0
0
0
0
Device Code
VIH
1
0
1
1
0
0
0
1
Hex
Data
20h
B1h
2.10
Erasure operation (applies to UV EPROM)
The erasure characteristics of the M27V160 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 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 erasure. The recommended
erasure procedure for M27V160 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 30 W-sec/cm2. The erasure time with this dosage is approximately
30 to 40 minutes using an ultraviolet lamp with 12000 µW/cm2 power rating. The M27V160
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.
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