CAT28LV64 CATALYST [Catalyst Semiconductor], CAT28LV64 Datasheet - Page 10

• Manufacturer Part Number: CAT28LV64
• Description: 64K-Bit CMOS PARALLEL E2PROM
• Manufacturer: CATALYST [Catalyst Semiconductor]

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
ORDERING INFORMATION
Doc. No. 25035-00 2/98
Notes:
(1)
* -40˚C to +125˚C is available upon request
The device used in the above example is a CAT28LV64NI-25T (PLCC, Industrial temperature, 250 ns Access Time, Tape & Reel).
WE
CE
DATA
ADDRESS
Company
Optional
Prefix
CAT
ID
DATA
ADDRESS
CE
WE
Device #
Product
Number
28LV64
1555
AA
0AAA
Package
P: PDIP
J: SOIC (JEDEC)
K: SOIC (EIAJ)
N: PLCC
T13: TSOP (8mmx13.4mm)
55
Suffix
1555
AA
1555
80
N
0AAA
55
Temperature Range
Blank = Commercial (0˚C to +70˚C)
I = Industrial (-40˚C to +85˚C)
A = Automotive (-40˚ to +105˚C)*
10
1555
AA
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.
1555
t WP
A0
2
PROM programmer (or for testing purposes) there
0AAA
55
I
t BLC
1555
ENABLED
BYTE OR
WRITES
20
PAGE
t WC
Speed
25: 250ns
30: 300ns
35: 350ns
-25
t WC
Tape & Reel
T: 500/Reel
SDP
RESET
DEVICE
UNPROTECTED
T
5094 FHD F13
5094 FHD F14
28LV64 F17