CAT28C256 CATALYST [Catalyst Semiconductor], CAT28C256 Datasheet - Page 10

• Manufacturer Part Number: CAT28C256
• Description: 32K-Bit Parallel E2PROM
• Manufacturer: CATALYST [Catalyst Semiconductor]

ORDERING INFORMATION
CAT28C256
To activate the software data protection, the device must
be sent three write commands to specific addresses with
specific data (Figure 9). This sequence of commands
(along with subsequent writes) must adhere to the page
write timing specifications (Figure 11). Once this is done,
all subsequent byte or page writes to the device must be
preceded by this same set of write commands. The data
protection mechanism is activated until a deactivate
sequence is issued regardless of power on/off transi-
tions. This gives the user added inadvertent write pro-
tection on power-up in addition to the hardware protec-
tion provided.
Figure 11. Software Data Protection Timing
Figure 12. Resetting Software Data Protection Timing
Doc. No. 25020-0A 2/98
Notes:
(1)
* -40˚C to +125˚C is available upon request
Company
The device used in the above example is a CAT28C256HNI-15T (100,000 Cycle Endurance, PLCC, Industrial temperature, 150ns
Access Time, Tape & Reel).
Optional
Prefix
CAT
ID
DATA
ADDRESS
CE
WE
WE
DATA
ADDRESS
CE
Device #
Product
Number
28C256
Endurance
Blank = 10,000 Cycle
H = 100,000 Cycle
5555
AA
H
5555
AA
Suffix
2AAA
55
2AAA
55
Package
P: PDIP
N: PLCC
T13: TSOP (8mmx13.4mm)
5555
80
N
10
Temperature Range
Blank = Commercial (0˚C to +70˚C)
I = Industrial (-40˚C to +85˚C)
A = Automotive (-40˚ to +105˚C)*
5555
t WP
A0
To allow the user the ability to program the device with
an E
is a software command sequence for deactivating the
data protection. The six step algorithm (Figure 10) will
reset the internal protection circuitry, and the device will
return to standard operating mode (Figure 12 provides
reset timing). After the sixth byte of this reset sequence
has been issued, standard byte or page writing can
commence.
5555
AA
2
PROM programmer (or for testing purposes) there
t BLC
2AAA
55
I
ENABLED
BYTE OR
WRITES
PAGE
5555
20
t WC
Speed
12: 120ns
15: 150ns
t WC
-15
Tape & Reel
T: 500/Reel
SDP
RESET
DEVICE
UNPROTECTED
T
5096 FHD F13
5096 FHD F14
28C256 F16