HD6473258CP10 Datasheet, PDF (221/301 Pages) Renesas Technology Corp – Hitachi Single-Chip Microcomputer

If a series of write errors occurs while the same PROM writer is in use, stop programming and
check the PROM writer and socket adapter for defects, using a microcomputer chip with a
windowed package and on-chip EPROM.
Please inform Hitachi of any abnormal conditions noted during programming or in screening of
program data after high-temperature baking.
11.3.5 Erasing of Data
The windowed package enables data to be erased by illuminating the window with ultraviolet light.
Table 11-9 lists the erasing conditions.
Table 11-9. Erasing Conditions
Item
Ultraviolet wavelength
Minimum illumination
Value
253.7 nm
15W·s/cm²
The conditions in table 11-9 can be satisfied by placing a 12000-µW/cm² ultraviolet lamp 2 or 3
centimeters directly above the chip and leaving it on for about 20 minutes.
11.4 Handling of Windowed Packages
(1) Glass Erasing Window: Rubbing the glass erasing window of a windowed package with a
plastic material or touching it with an electrically charged object can create a static charge on the
window surface which may cause the chip to malfunction.
If the erasing window becomes charged, the charge can be neutralized by a short exposure to
ultraviolet light. This returns the chip to its normal condition, but it also reduces the charge stored
in the floating gates of the PROM, so it is recommended that the chip be reprogrammed afterward.
Accumulation of static charge on the window surface can be prevented by the following
precautions:
x When handling the package, ground yourself. Don’t wear gloves. Avoid other possible sources
of static charge.
y Avoid friction between the glass window and plastic or other materials that tend to accumulate
static charge.
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