8051AH Datasheet, PDF (20/21 Pages) Intel Corporation – MCS51 8-BIT CONTROL-ORIENTED MICROCONTROLLERS

MCS” 51 CONTROLLER
ERASURE CHARACTERISTICS
Erasure of the EPROM begins to occur when the
8752BH is exposed to light with wavelengths shorter
than approximately 4,000 Angstroms. Since sunlight
and fluorescent lighting have wavelengths in this
range, exposure to these light sources over an ex-
tended time (about 1 week in sunlight, or 3 years in
room-level fluorescent lighting) could cause inadver-
tent erasure. If an application subjects the device to
this type of exposure, it is suggested that an opaque
label be placed over the window.
The recommended erasure procedure is exposure
to ultraviolet light (at 2537 Angstroms) to an integrat-
ed dose of at lease 15 W-see/cm. Exposing the
EPROM to an ultraviolet lamp of 12,000 pW/cm rat-
ing for 30 minutes, at a distance of about 1 inch,
should be sufficient.
Erasure leaves the array in an all Is state.
EPROM PROGRAMMING AND VERIFICATION CHARACTERISTICS
(T,4 = 21°C to 27”C, Vcc = 5.OV + 10%, Vss = OV)
Symbol
Parameter
Min
Max
Vpp
Programming Supply Voltage
12.5
13.0
Ipp
Programming Supply Current
50
1/TCLCL
Oscillator Frequency
4
8
TAVGL
Address Setup to PROG Low
48TCLCL
TGHAX
Address Hold After PROG
48TCLCL
TDVGL
Data Setup to PROG Low
48TCLCL
TGHDX
Data Hold After PROG
48TCLCL
TEHSH
P2.7 (ENABLE) High to Vpp
48TCLCL
TSHGL
Vpp Setup to PROG Low
10
TGHSL
Vpp Hold After PROG
10
TGLGH
TAVQV
TELQV
PROG Width
Address to Data Valid
ENABLE Low to Data Valid
90
110
48TCLCL
48TCLCL
TEHQZ
Data Float After ENABLE
o
48TCLCL
TGHGL
PROG High to PROG Low
10
Units
v
mA
MHz
ps
ps
ps
ps
EPROM PROGRAMMING AND VERIFICATION WAVEFORMS
‘::=&z
PROGRAMMING
ADDRESS
TDVGL
TAVGL
DATA IN
~
Pu&
.~-TGHDX
TGHAX
VERIFICATION
ADDRFSS
TAvQV
DATA OUT
}
~wpp
P2.7
TSHGL
TGLGH
d
TGHGL
TGHsL
t
[A/HIGH
TELQV
L
TEHQZ
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