ST7263
1.5 EPROM/OTP PROGRAM MEMORY
The program memory of the ST72T63 may be pro-
grammed using the EPROM programming boards
available from STMicroelectronics (see Table 26).
1.5.1 EPROM ERASURE
ST72Exxx EPROM devices are erased by expo-
sure to high intensity UV light admitted through the
transparent window. This exposure discharges the
floating gate to its initial state through induced
photo current.
It is recommended that the ST72Exxx devices be
kept out of direct sunlight, since the UV content of
sunlight can be sufficient to cause functional fail-
ure. Extended exposure to room level fluorescent
lighting may also cause erasure.
An opaque coating (paint, tape, label, etc...)
should be placed over the package window if the
product is to be operated under these lighting con-
ditions. Covering the window also reduces IDD in
power-saving modes due to photo-diode leakage
currents.
An Ultraviolet source of wave length 2537 Å yield-
ing a total integrated dosage of 15 Watt-sec/cm2 is
required to erase the ST72Exxx. The device will
be erased in 15 to 30 minutes if such a UV lamp
with a 12mW/cm2 power rating is placed 1 inch
from the device window without any interposed fil-
ters.
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