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SILICON GATE MOS 8708/8704
PROGRAMMING OPERATION
Description
Initially, and
after
each erasure, all bits
of
the
8708/8704
are
in
the
"1"
state
(Output
High).
Information
is
introduced
by
select-
ively
programming
"0"
into
the
desired
bit
locations.
The
circuit
is
set
up
for
programming
operation
by
raising
the
CS/WE
input
(Pin 20)
to
+12V.
The
word
address
is
selected in
the
same
manner
as in
the
read
mode.
Data
to
be programmed are presented, 8-bits in parallel,
to
the
data
output
lines
(01-08).
Logic levels
for
address and
data
lines
and
the
supply
voltages are
the
same
as
for
the
read mode.
After
address
and
data
set
up
one
program
pulse (Vp) per address
is
applied
to
the
program
input
(Pin 18).
One
pass
through
all addresses
to
be
programmed
is
defined as a program loop.
The
number
of
loops (N) required
is
a
function
of
the
program pulse
width
(tpw)
according
to
N x tpw
~
100
ms.
For
program verification, program loops
and
read loops
may
be
alternated
as
shown
in
waveform
B.
Program Characteristics
TA
=25°C,
Vcc
=+5V ±5%,
Voo
=
+12V
±5%, V
ss
=
-5V
±5%, Vss =
OV,
CS/WE =
+12V,
Unless
Otherwise
Noted.
Symbol
Parameter
Min.
Typ.
Max.
Units
tAS
Address
Setup
Time
10
llS
tcss
CS/WE
Setup
Time
10
llS
tos
Data
Setup
Time
10
llS
tAH
Address Hold
Time
1
llS
tCH
CS/WE Hold
Time
.5
lls
tOH
Data Hold
Time
1
lls
tOF
Chip Deselect
to
Output
Float
Delay
0
120
ns
tOPR
Program
To
Read Delay
10
llS
tpw
Program Pulse Width
.1
1.0
ms
tpR
Program Pulse Rise
Time
.5
2.0
llS
tpF
Program Pulse Fall
Time
.5
2.0
llS
Ip
Programming
Current
10
20
rnA
Vp
Program Pulse
Amplitude
25
27
V
NOTE: Intels standard
product
warranty
applies
only
to
devices programmed
to
specifications described herein.
Erasing Procedure
The
8708/8704
may
be erased
by
exposu
re
to
high intensity short-wave
ultraviolet
Iight
at
a wavelength
of
2537
A.
The
recom-
mended
integrated
dose. (Le.,
UV
intensity
x
exposure
time)
is
10W-sec/cm
2
.
Examples
of
ultraviolet
sources
which
can
erase
the
8708/8704
in
20
to
30
minutes
are
the
Model UVS-54 and Model S-52 short-wave
ultraviolet
lamps
manufactured
by
Ultra-Violet
Products,
Inc.
(5114
Walnut
Grove Avenue, San Gabriel, California).
The
lamps
should
be used
without
short-wave filters, and
the
8708/8704
to
be
erased
should
be
placed
about
one
inch
away
from
the
lamp
tubes.
5-48