27C512-120 Просмотр технического описания (PDF) - STMicroelectronics
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27C512-120 Datasheet PDF : 18 Pages
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Table 11. Programming Mode AC Characteristics (1)
(TA = 25 °C; VCC = 6.25V ± 0.25V; VPP = 12.75V ± 0.25V)
Symbol
Alt
Parameter
Test Condition
Min
tAVEL
tAS Address Valid to Chip Enable Low
2
tQVEL
tDS Input Valid to Chip Enable Low
2
tVCHEL
tVCS VCC High to Chip Enable Low
2
tVPHEL
tOES VPP High to Chip Enable Low
2
tVPLVPH
tPRT VPP Rise Time
50
tELEH
tPW Chip Enable Program Pulse Width (Initial)
95
tEHQX
tDH Chip Enable High to Input Transition
2
tEHVPX
tOEH Chip Enable High to VPP Transition
2
tVPLEL
tVR VPP Low to Chip Enable Low
2
tELQV
tDV Chip Enable Low to Output Valid
tEHQZ (2)
tDFP Chip Enable High to Output Hi-Z
0
tEHAX
tAH Chip Enable High to Address Transition
0
Note: 1. VCC must be applied simultaneously with or before VPP and removed simultaneously or after VPP.
2. Sampled only, not 100% tested.
M27C512
Max Unit
µs
µs
µs
µs
ns
105
µs
µs
µs
µs
1
µs
130
ns
ns
Programming
When delivered (and after each erasure for UV
EPROM), all bits of the M27C512 are in the ’1’
state. Data is introduced by selectively program-
ming ’0’s into the desired bit locations. Although
only ’0’s will be programmed, both ’1’s and ’0’s can
be present in the data word. The only way to
change a ’0’ to a ’1’ is by die exposure to ultraviolet
light (UV EPROM). The M27C512 is in the pro-
gramming mode when VPP input is at 12.75V and
E is pulsed to VIL. The data to be programmed is
applied to 8 bits in parallel to the data output pins.
The levels required for the address and data in-
puts are TTL. VCC is specified to be 6.25V ±
0.25V. The M27C512 can use PRESTO IIB Pro-
gramming Algorithm that drastically reduces the
programming time (typically less than 6 seconds).
Nevertheless to achieve compatibility with all pro-
gramming equipments, PRESTO Programming
Algorithm can be used as well.
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