M27C801-100B STMicroelectronics, M27C801-100B Datasheet - Page 10

• Manufacturer Part Number: M27C801-100B
• Description: 8 Mbit 1Mb x 8 UV EPROM and OTP EPROM
• Manufacturer: STMicroelectronics

M27C801
On-Board Programming
The M27C801 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 M27C801. To activate the ES
mode, the programming equipment must force
11.5V to 12.5V on address line A9 of the
M27C801. Two identifier bytes may then be se-
quenced from the device outputs by toggling ad-
dress line A0 from V
lines must be held at V
ture mode. Byte 0 (A0 = V
ufacturer code and byte 1 (A0 = V
identifier
M27C801, these two identifier bytes are given in
Table 4 and can be read-out on outputs Q7 to Q0.
10/16
code.
For
IL
IL
to V
the
during Electronic Signa-
IL
) represents the man-
IH
. All other address
STMicroelectronics
IH
) the device
5 C am-
ERASURE OPERATION (applies to UV EPROM)
The erasure characteristics of the M27C801 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 fluorescent lighting could erase a typical
M27C801 in about 3 years, while it would take ap-
proximately 1 week to cause erasure when ex-
posed to direct sunlight. If the M27C801 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 M27C801 window to
prevent unintentional erasure. The recommended
erasure procedure for the M27C801 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 30 W-sec/cm
age is approximately 30 to 40 minutes using an ul-
traviolet lamp with 12000 W/cm
The M27C801 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.
2
. The erasure time with this dos-
2
power rating.