M27V322(2000) View Datasheet(PDF) - STMicroelectronics
Part Name
Description
Manufacturer
M27V322 Datasheet PDF : 13 Pages
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M27V322
Figure 2A. DIP Connections
A18
A17
A7
A6
A5
A4
A3
A2
A1
A0
E
VSS
GVPP
Q0
Q8
Q1
Q9
Q2
Q10
Q3
Q11
1
42 A19
2
41 A8
3
40 A9
4
39 A10
5
38 A11
6
37 A12
7
36 A13
8
35 A14
9
34 A15
10
33 A16
M27V322
11
32 A20
12
31 VSS
13
30 Q15
14
29 Q7
15
28 Q14
16
27 Q6
17
26 Q13
18
25 Q5
19
24 Q12
20
23 Q4
21
22 VCC
AI03051
DEVICE OPERATION
The operating modes of the M27V322 are listed in
the Operating Modes Table. A single power supply
is required in the read mode. All inputs are TTL
compatible except for VPP and 12V on A9 for the
Electronic Signature.
Read Mode
The M27V322 has a word-wide organization. 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 independent of device selection.
Assuming that the addresses are stable, the ad-
dress access time (tAVQV) is equal to the delay
Table 1. Signal Names
A0-A20
Address Inputs
Q0-Q15
Data Outputs
E
Chip Enable
GVPP
Output Enable / Program Supply
VCC
Supply Voltage
VSS
Ground
from E to output (tELQV). Data is available at the
output after a delay of tGLQV from the falling edge
of GVPP, assuming that E has been low and the
addresses have been stable for at least tAVQV-
tGLQV.
Standby Mode
The M27V322 has a standby mode which reduces
the supply current from 30mA to 30µA. The
M27V322 is placed in the standby mode by apply-
ing a CMOS high signal to the E input.When in the
standby mode, the outputs are in a high imped-
ance state, independent of the GVPP input.
Two Line Output Control
Because EPROMs are usually used in larger
memory arrays, this product features a 2 line con-
trol function which accommodates the use of mul-
tiple memory connection. The two line control
function allows:
a. the lowest possible memory power dissipation,
b. complete assurance that output bus contention
will not occur.
For the most efficient use of these two control
lines, E should be decoded and used as the prima-
ry device selecting function, while GVPP 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 deselect-
ed memory 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.
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