M27C512-90XN6X STMicroelectronics, M27C512-90XN6X Datasheet - Page 3

• Manufacturer Part Number: M27C512-90XN6X
• Description: 512 Kbit 64Kb x8 UV EPROM and OTP EPROM
• Manufacturer: STMicroelectronics

Table 3. Operating Modes
Notes : X = V
Table 4. Electronic Signature
Note: Outputs Q8-Q15 are set to ’0’.
DEVICE OPERATION
The operating modes of the M27C516 are listed in
the Operating Modes table. A single power supply
is required in the read mode. All inputs are TTL
levels except for G and 12V on A9 for Electronic
Signature.
Read Mode
The M27C516 has two control functions, both of
which must be logically active in order to obtain
data at the outputs. Chip Enable (E) is the power
control and should be used for device selection.
Output Enable (G) is the output control and should
be used to gate data to the output pins, inde-
pendent of device selection. Assuming that the
addresses are stable, the address access time
(t
Data is available at the output after a delay of t
from the falling edge of G, assuming that E has
been low and the addresses have been stable for
at least t
Standby Mode
The M27C516 has a standby mode which reduces
the supply current from 30mA to 100 A. The
AVQV
Manufacturer’s Code
Device Code
Read
Output Disable
Program
Verify
Program Inhibit
Standby
Electronic Signature
) isequal to the delay from E to output(t
Identifier
AVQV
IH
or V
Mode
-t
IL
GLQV
, V
ID
= 12V
.
V
A0
V
0.5V
IH
IL
Q7
0
0
V
V
V
V
V
V
V
E
IH
IH
IL
IL
IL
IL
IL
Q6
0
0
ELQV
GLQV
V
Q5
V
V
V
G
).
X
X
X
1
0
IH
IL
IL
IL
M27C516 is placed in the standby mode by apply-
ing a CMOS high signal to the E input. When in the
standbymode, the outputs are in a high impedance
state, independent of the G input.
Two Line Output Control
Because OTP EPROMs are usually used in larger
memory arrays, the product featuresa 2 line control
function which accommodates the use of multiple
memory connection. The two line control function
allows:
a. the lowest possible memory power dissipation,
b. complete assurance that output bus contention
For the most efficientuse of these two control lines,
E should be decoded and used as the primary
device selecting function, while G should be made
a common connection to all devices in the array
and connected to the READ line from the system
control bus. This ensures that all deselected mem-
ory devices are in their low power standby mode
and that the output pins are only active when data
is required from a particular memory device.
Q4
0
0
will not occur.
V
IL
V
V
V
Pulse
P
X
X
X
IH
IH
IH
Q3
0
1
Q2
0
1
V
A9
X
X
X
X
X
X
ID
Q1
0
1
V
V
V
V
V
V
V
V
CC
CC
CC
CC
PP
PP
PP
PP
Q0
0
1
M27C516
Q0 - Q15
Hex Data
Data Out
Data Out
Data In
Codes
Hi-Z
Hi-Z
Hi-Z
20h
0Fh
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