M27C64A STMICROELECTRONICS [STMicroelectronics], M27C64A Datasheet - Page 8

• Manufacturer Part Number: M27C64A
• Description: 64K (8K x 8) UV EPROM and OTP ROM
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

M27C64A
DEVICE OPERATIONS (cont’d)
at 12.5V, will program that M27C64A. A high level
E input inhibits the other M27C64A from being
programmed.
Program Verify
A verify (read) should be performed on the pro-
grammed bits to determine that they were correctly
programmed. The verify is accomplished with E
and G at V
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 the 25 C
temperature range that is required when program-
ming the M27C64A. To activate this mode, the
programming equipmentmust force11.5V to 12.5V
on address line A9 of the M27C64A, 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
and byte 1 (A0=V
ORDERING INFORMATION SCHEME
For a list of available options (Speed, 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.
8/11
-15
-20
-25
-30
PP
=V
CC
Speed
=5V. Two identifier bytes may then be
IL
150 ns
200 ns
250 ns
300 ns
, P at V
IL
) represents the manufacturer code
Example:
IH
) the device identifier code. For
IH
, V
IL
PP
IL
to V
during Electronic Signa-
at 12.5V and V
M27C64A
F
C
IH
. All other address
Package
PLCC32
FDIP28W
5 C ambient
CC
at 6V.
-15 F
1 TR
the SGS-THOMSON M27C64A, these two identi-
fier bytes are given in Table 4 and can be read-out
on outputs Q0 to Q7.
ERASURE OPERATION (applies to UV EPROM)
The erasure characteristics of the M27C64A 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 wave-
lengths in the 3000-4000 Å range. Research
shows that constant exposure to room level fluo-
rescent lighting could erase a typical M27C64A in
about 3 years, while it would take approximately 1
week to cause erasure when exposed to direct
sunlight. If the M27C64A 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 M27C64Awindow to prevent unintentional era-
sure. The recommended erasure procedure for
the M27C64A is exposure to short wave ultraviolet
light which has a 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 approximately
15 to 20 minutes using an ultraviolet lamp with
12000 uW/cm
be placed within 2.5 cm (1 inch) of the lamp tubes
during the erasure. Some lamps have a filter on
their tubeswhich should be removed beforeerasure.
Temperature Range
1
6
0 to 70 C
–40 to 85 C
2
powerrating. The M27C64A should
TR
X
Option
Additional
Tape & Reel
Packing
Burn-in
2
.