A.C. CHARACTERISTICS - READ OPERATION
28C64A-1 28C64A-2 28C64A-3 28C64A-4
Symbol Parameters Min Max Min Max Min Max Min MaxUnit
tacc Address to 120 150 200 250 ns
Output Delay
tce CE to Output 120 150 200 250 ns
Delay
toe OE to Output 70 90 110 150 ns
tdf OE to Output 0 40 0 60 0 90 0 90 n s
In High Z
toh Output Hold 0000ns
from Address
Changes, Chip
Enable or
Output Enable
Whichever
Occurs First
Symbol Parameter Condition Min Max Units
Icc Active Vcc CE=OE=Vil; All I/O 50 (C) mA
Current Open, Min Read or 70 (I) mA
Write Cycle Time 90 (M) mA
Isb1 CMOS CE=Vcc-0.3 V to 200 (C) µA
Standby Vcc+1 V 300 (I&M) µA
Current
Isb2 TTL Standby CE=Vih, OE=Vil, 3 mA
Current All I/O Open, Other
Inputs=Vcc Max
Vin=Vcc Max
Iil Input 1 µA
Leakage
Current
Iol Output 10 µA
Leakage
Current
Vil Input Low -0.1 -0.8 V
Voltage
Vih Input High 2 Vcc+0.3 V
Voltage
Vol Output Low Iol=2.1 mA 0.45 V
Voltage
Voh Output High Ioh=-0.45 mA 2.4 V
Voltage
28C64A
Turbo IC, Inc.
D.C. CHARACTERISTICS
erase cycle; typically takes 20 msec. After a software chip clear operation has been completed, all 64K bit locations of memory show
high level at read operation mode.
d.) Software Autoclear Disable Mode
This software algorithm disables the internal automatic clear before
write cycle. Table 4 shows the six steps needed to perform the autoclear disable mode:
Step Mode Address A12-A0 Data I/O 7-0
1 Page Write 1555 Hex AA Hex
2 Page Write 0AAA Hex 55 Hex
3 Page Write 1555 Hex 80 Hex
4 Page Write 1555 Hex AA Hex
5 Page Write 0AAA Hex 55 Hex
6 Page Write 1555 Hex 40 Hex
7-70 Page Write Address Data
Page write operation using the software autoclear disable mode will
reduce programming time to typically 5 msec. The page write using
software autoclear disable mode is usually used after a chip clear or
a software chip clear operation. At the end of the six steps sequence,
the autoclear before write is disabled and will stay that wa y unless a
power-down occurs or the software autoclear enable procedure is
initiated.
e.) Software Autoclear Enable Mode
Automatic page clear before page write can be restored to 28C64A
either by Vcc power-down or by software autoclear enable mode.
Table 5 shows the six steps page write procedure needed to enable
software autoclear mode:
Step Mode Address A12-A0 Data I/O 7-0
1 Page Write 1555 Hex AA Hex
2 Page Write 0AAA Hex 55 Hex
3 Page Write 1555 Hex 80 Hex
4 Page Write 1555 Hex AA Hex
5 Page Write 0AAA Hex 55 Hex
6 Page Write 1555 Hex 50 Hex
7-70 Page Write Address Data
A.C. Read Wave Forms
A.C. TEST CONDITIONS
Output Load : 1 TTL Load and Cl=100 pF
Input Rise and Fall Times : < 10 ns
Input Pulse Level : 0 V to 3 V
Timing Measurement Reference Level : 1.5 V
ABSOLUTE MAXIMUM STRESS RANGES *
TEMPERATURE
Storage: -65° C to 150° C
Under Bias: -55° C to 125° C
ALL INPUT OR OUTPUT VOLTAGES
with respect to Vss +6 V to -0.3 V
“Absolute Maximum Ratings” ma y cause permanent damage to the device. This is a stress rating
only and functional operation of the device at
these or any other conditions above those indicated in the operation section of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may
affect device reliability.
RECOMMENDED OPERATING CONDITIONS
Temperature Range: Commercial: 0° C to 70° C
Industrial: -40° C to 85° C
Military: -55° C to 125° C
Vcc Supply Voltage:5 V ± 10%
Endurance: 100,000 Cycles/Byte (Typical)
Data Retention: 10 Years
(C) = COMMERICAL
(I) = INDUSTRIAL
(M) = MILITAR Y
tacc
ADDRESS VALID
ADDRESS
CE
OE
OUTPUT HIGH-Z
toe
tce
tdf
toh
OUTPUT VALID
HIGH-Z