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參數(shù)資料
| 型號： | M87C257-20 |
| 廠商： | 意法半導(dǎo)體 |
| 英文描述： | ADDRESS LATCHED 256K (32K x 8) UV EPROM and OTP EPROM |
| 中文描述： | 地址鎖存256K（32K的× 8）紫外線存儲器和OTP存儲器 |
| 文件頁數(shù)： | 9/13頁 |
| 文件大小： | 143K |
| 代理商： | M87C257-20 |
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
±
5
°
C ambient
temperature range that is required when program-
ming the M87C257.
To activate the ES mode, the programming equip-
ment must force 11.5V to 12.5V on address line A9
of the M87C257, with V
CC
= V
PP
= 5V. Two identifier
bytes may then be sequenced from the device
outputs by toggling address line A0 from V
IL
to V
IH
.
All other address lines must be held at V
IL
during
Electronic Signature mode. Byte 0 (A0=V
IL
) repre-
sents the manufacturer code and byte 1 (A0=V
IH
)
the device identifier code. When A9 = V
ID
, AS need
not be toggled to latch each identifier address. For
the SGS-THOMSON M87C257, these two identi-
fier bytes are given in Table 4 and can be read-out
on outputs Q0 to Q7.
ERASURE OPERATION (applies for UV EPROM)
The erasure characteristics of the M87C257 is such
that erasure begins when the cells are exposed to
light with wavelengths shorter than approximately
4000 . It should be noted that sunlight and some
type of fluorescent lamps have wavelengths in the
3000-4000 range. Research shows that constant
exposure to room level fluorescent lighting could
erase a typical M87C257 in about 3 years, while it
would take approximately 1 week to cause erasure
when exposed to direct sunlight. If the M87C257 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 M87C257 window to
prevent unintentional erasure. The recommended
erasure procedure for the M87C257 is exposure to
short wave ultraviolet light which has wavelength
2537. The integrated dose (i.e. UV intensity x
exposure time) for erasure should be a minimum
of 15 W-sec/cm
2
. The erasure time with this dos-
age is approximately 15 to 20 minutes using an
ultraviolet lamp with 12000
μ
W/cm
2
power rating.
The M87C257 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.
9/13
M87C257
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| M87C257-20C1TR | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:ADDRESS LATCHED 256K 32K x 8 UV EPROM and OTP EPROM |
| M87C257-20C1X | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:ADDRESS LATCHED 256K 32K x 8 UV EPROM and OTP EPROM |
| M87C257-20C3TR | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:ADDRESS LATCHED 256K 32K x 8 UV EPROM and OTP EPROM |
| M87C257-20C3X | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:ADDRESS LATCHED 256K 32K x 8 UV EPROM and OTP EPROM |
| M87C257-20C6TR | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:ADDRESS LATCHED 256K 32K x 8 UV EPROM and OTP EPROM |
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