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M27128A-3F1 View Datasheet(PDF) - STMicroelectronics

Part NameDescriptionManufacturer
M27128A-3F1 NMOS 128K (16K x 8) UV EPROM ST-Microelectronics
STMicroelectronics ST-Microelectronics
M27128A-3F1 Datasheet PDF : 10 Pages
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M27128A
Program Verify
A verify should be performed on the programmed
bits to determine that they were correctly pro-
grammed. The verify is accomplished with G = VIL,
E = VIL, P = VIH and VPP at 12.5V.
Electronic Signature
The Electronic Signature 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.
This mode is functional in the25°C ± 5°C ambient
temperature range that is required when program-
ming the M27128A.
To activate this mode, the programming equipment
must force 11.5V to 12.5V on address line A9 of the
M27128A. Two identifier bytes may then be se-
quenced from the device outputs by toggling ad-
dress 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 manufac-
turer code and byte 1 (A0 = VIH) the device identifier
code. For the SGS-THOMSON M27128A, these
two identifier bytes are given below.
ERASURE OPERATION (applies to UV EPROM)
The erasure characteristic of the M27128A 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 M27128A in about 3 years, while it
would take approximately 1 week to cause erasure
when exposed to direct sunlight. If the M27128A 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 M27128A window to
prevent unintentional erasure. The recommended
erasure procedure for the M27128A 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 ultra-
violet lamp with 12000 µW/cm2 power rating. The
M27128A 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 re-
moved before erasure.
ORDERING INFORMATION SCHEME
Example:
M27128A -2 F 1
Speed and VCC Tolerance
-2
200 ns, 5V ±5%
blank 250 ns, 5V ± 5%
-3
300 ns, 5V ± 5%
-4
450 ns, 5V ± 5%
-20 200 ns, 5V ± 10%
-25 250 ns, 5V ± 10%
-30 300 ns, 5V ± 10%
Package
F
FDIP28W
Temperature Range
1 0 to 70 °C
6 –40 to 85 °C
For a list of available options (Speed, VCC Tolerance, Package, etc...) refer to the current Memory Shortform
catalogue.
For further information on any aspect of this device, please contact SGS-THOMSON Sales Office nearest
to you.
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