CAT1161, CAT1162
Hardware Data Protection
until VCC reaches the reset threshold (power up)
VTH. Any attempt to access the internal EEPROM
is not recognized and an ACK will not be sent on
The CAT1161/2 is designed with the following
hardware data protection features to provide a high
degree of data integrity.
¯¯¯¯¯¯
the SDA line when RESET or RESET is active.
Reset Threshold Voltage
(1) The CAT1161/2 features a WP pin. When the WP
pin is tied high the entire memory array becomes
write protected (read only).
(2) The VCC sense provides write protection when VCC
falls below the reset threshold value (VTH). The
VCC lock out inhibits writes to the serial EEPROM
whenever VCC falls below (power down) VTH or
The CAT1161/2 is offered with five reset threshold
voltage ranges. They are 4.50 ÷ 4.75V, 4.25 ÷ 4.50V,
3.00 ÷ 3.15V, 2.85 ÷ 3.00V and 2.55 ÷ 2.70V.
Figure 2. Bus Timing
t
t
t
F
HIGH
R
t
t
LOW
LOW
SCL
t
t
HD:DAT
SU:STA
t
t
t
t
HD:STA
SU:DAT
SU:STO
SDA IN
BUF
t
t
DH
AA
SDA OUT
Figure 3. Write Cycle Timing
SCL
SDA
8TH BIT
BYTE n
ACK
t
WR
STOP
CONDITION
START
CONDITION
ADDRESS
Figure 4. Start/Stop Timing
SDA
SCL
START BIT
STOP BIT
© 2007 Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
6
Doc. No. 3002 Rev. F
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