4
AT28BV256
0273H–PEEPR–10/04
specifications. The data in the 3-byte command sequence is not written to the device; the
address in the command sequence can be utilized just like any other location in the device.
Any attempt to write to the device without the 3-byte sequence will start the internal write tim-
ers. No data will be written to the device; however, for the duration of t
WC
, read operations will
effectively be polling operations.
DEVICE IDENTIFICATION: An extra 64 bytes of EEPROM memory are available to the user
for device identification. By raising A9 to 12V ± 0.5V and using address locations 7FC0H to
7FFFH the additional bytes may be written to or read from in the same manner as the regular
memory array.
Notes: 1. X can be V
IL
or V
IH
.
2. Refer to AC programming waveforms.
3. V
H
= 12.0V ± 0.5V.
DC and AC Operating Range
AT28BV256-20 AT28BV256-25
Operating Temperature (Case)
Com. 0°C - 70°C 0°C - 70°C
Ind. -40°C - 85°C -40°C - 85°C
V
CC
Power Supply 2.7V - 3.6V 2.7V - 3.6V
Operating Modes
Mode CE OE WE I/O
Read V
IL
V
IL
V
IH
D
OUT
Write
(2)
V
IL
V
IH
V
IL
D
IN
Standby/Write Inhibit V
IH
X
(1)
XHigh Z
Write Inhibit X X V
IH
Write Inhibit X V
IL
X
Output Disable X V
IH
XHigh Z
Chip Erase V
IL
V
H
(3)
V
IL
High Z
DC Characteristics
Symbol Parameter Condition Min Max Units
I
LI
Input Load Current V
IN
= 0V to V
CC
+ 1V 10 µA
I
LO
Output Leakage Current V
I/O
= 0V to V
CC
10 µA
I
SB
V
CC
Standby Current CMOS CE = V
CC
- 0.3V to V
CC
+ 1V
Com. 20 µA
Ind. 50 µA
I
CC
V
CC
Active Current f = 5 MHz; I
OUT
= 0 mA 15 mA
V
IL
Input Low Voltage 0.6 V
V
IH
Input High Voltage 2.0 V
V
OL
Output Low Voltage I
OL
= 1.6 mA 0.3 V
V
OH
Output High Voltage I
OH
= -100 µA 2.0 V
