M27W401-100F6TR STMICROELECTRONICS [STMicroelectronics], M27W401-100F6TR Datasheet - Page 9

• Manufacturer Part Number: M27W401-100F6TR
• Description: 4 Mbit 512Kb x 8 Low Voltage UV EPROM and OTP EPROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

On-Board Programming
The M27W401 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
bient temperature range that is required when pro-
gramming the M27W401. To activate the ES
mode, the programming equipment must force
11.5V to 12.5V on address line A9 of the
M27W401 with V
bytes may then be sequenced from the device out-
puts by toggling address line A0 from V
other address lines must be held at V
Electronic Signature mode. Byte 0 (A0 = V
resents the manufacturer code and byte 1
(A0 = V
STMicroelectronics M27W401, these two identifier
bytes are given in Table 4 and can be read-out on
outputs Q7 to Q0. Note that the M27W401 and
M27C4001 have the same identifier bytes.
IH
) the device identifier code. For the
PP
= V
CC
= 5V. Two identifier
IL
to V
IL
5 C am-
IL
during
IH
) rep-
. All
ERASURE OPERATION (applies to UV EPROM)
The erasure characteristics of the M27W401 are
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. Data
shows that constant exposure to room level fluo-
rescent lighting could erase a typical M27W401 in
about 3 years, while it would take approximately 1
week to cause erasure when exposed to direct
sunlight. If the M27W401 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 M27W401 window to prevent unintentional
erasure. The recommended erasure procedure for
the M27W401 is exposure to short wave ultraviolet
light which has 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
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.
W/cm
2
power rating. The M27W401
M27W401
9/15
2
.