M27C4002-12XJ1TR STMicroelectronics, M27C4002-12XJ1TR Datasheet - Page 9

• Manufacturer Part Number: M27C4002-12XJ1TR
• Description: 4 Mbit 256Kb x16 UV EPROM and OTP EPROM
• Manufacturer: STMicroelectronics

On-Board Programming
The M27C4002 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 correspondingprogramming algorithm. The
ES mode is functional in the 25 C
temperature range that is required when program-
ming the M27C4002. To activate the ES mode, the
programming equipmentmust force 11.5Vto 12.5V
on address line A9 of the M27C4002 with
V
sequenced from the device outputs by toggling
address line A0 from V
lines must be held at V
ture mode. Byte 0 (A0=V
facturer code and byte 1 (A0=V
iden tifier code.
M27C4002, these two identifier bytes are given in
Table 4 and can be read-out on outputs Q0 to Q7.
PP
=V
CC
=5V. Two identifier bytes may then be
For the STMicroelectronics
IL
IL
IL
to V
during Electronic Signa-
) represents the manu-
IH
. All other address
IH
) the device
5 C ambient
ERASURE OPERATION (applies to UV EPROM)
The erasure characteristics of the M27C4002 are
such that erasure begins when the cells are ex-
posed to light with wavelengths shorter than ap-
proximately 4000 Å.
sunlight and some type of fluorescent lamps have
wavelengths in the 3000-4000Å range. Research
shows that constant exposure to room level fluo-
rescent lighting could erase a typical M27C4002 in
about 3 years, while it would take approximately 1
week to cause erasure when exposed to direct
sunlight. If the M27C4002 is to be exposed to
these types of lighting conditions for extended pe-
riods of time, it is suggested that opaque labels be
put over the M27C4002 window to prevent uninten-
tional erasure. The recommended erasure proce-
dure for the M27C4002 is exposure to short wave
ultraviolet light which has wavelength 2537 Å. The
integrated 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 approximately
15 to 20 minutes using an ultraviolet lamp with
12000 W/cm
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.
2
power rating.
It should be noted that
The M27C4002
M27C4002
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