M27C256B
Table 2. Absolute Maximum Ratings (1)
Symbol
Parameter
Value
Unit
TA
Ambient Operating Temperature (3)
–40 to 125
°C
TBIAS
Temperature Under Bias
–50 to 125
°C
TSTG
VIO (2)
Storage Temperature
Input or Output Voltages (except A9)
–65 to 150
°C
–2 to 7
V
VCC
VA9 (2)
Supply Voltage
A9 Voltage
–2 to 7
V
–2 to 13.5
V
VPP
Program Supply Voltage
–2 to 14
V
Notes: 1. Except for the rating ”Operating Temperature Range”, stresses above those listed in the Table ”Absolute Maximum Ratings”
may cause permanent damage to the device. These are stress ratings only and operation of the device at these or any other
conditions above those indicated in the Operating sections of this specification is not implied. Exposure to Absolute Maximum
Rating conditions for extended periods may affect device reliability. Refer also to the STMicroelectronics SURE Program and other
relevant quality documents.
2. Minimum DC voltage on Input or Output is –0.5V with possible undershoot to –2.0V for a period less than 20ns. Maximum DC
voltage on Output is VCC +0.5V with possible overshoot to VCC +2V for a period less than 20ns.
3. Depends on range.
Table 3. Operating Modes
Mode
E
G
A9
VPP
Q0 - Q7
Read
VIL
VIL
X
VCC
Data Out
Output Disable
VIL
VIH
X
VCC
Hi-Z
Program
VIL Pulse
VIH
X
VPP
Data In
Verify
VIH
VIL
X
VPP
Data Out
Program Inhibit
VIH
VIH
X
VPP
Hi-Z
Standby
VIH
X
X
VCC
Hi-Z
Electronic Signature
VIL
VIL
VID
VCC
Codes
Note: X = VIH or VIL, VID = 12V ± 0.5V
Table 4. Electronic Signature
Identifier
A0
Q7
Q6
Q5
Q4
Q3
Q2
Q1
Q0 Hex Data
Manufacturer’s Code VIL
0
0
1
0
0
0
0
0
20h
Device Code
VIH
1
0
0
0
1
1
0
1
8Dh
Two Line Output Control
BecauseEPROMs are usually used in larger mem-
ory arrays, this product features a 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
will not occur.
For the most efficientuse of thesetwo controllines,
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 desired from a particular memory device.
3/15