Preliminary Information
64K
X40626
Dual Voltage CPU Supervisor with 64K Serial EEPROM
DESCRIPTION
8K x 8 Bit
FEATURES
• Dual voltage monitoring
—V
2Mon
operates independent of V
CC
• Watchdog timer with selectable timeout intervals
• Low V
CC
detection and reset assertion
—Four standard reset threshold voltages
—User programmable V
TRIP
threshold
—Reset signal valid to V
CC
=1V
• Low power CMOS
—20µA max standby current, watchdog on
—1µA standby current, watchdog OFF
• 64Kbits of EEPROM
—64 byte page size
• Built-in inadvertent write protection
—Power-up/power-down protection circuitry
—Protect 0, 1/4, 1/2, all or 64, 128, 256 or 512
bytes of EEPROM array with programmable
Block Lock
™
protection
• 400kHz 2-wire interface
—Slave addressing supports up to 4 devices on
the same bus
• 2.7V to 5.5V power supply operation
• Available Packages
—14-lead SOIC
—14-lead TSSOP
BLOCK DIAGRAM
V2MON
V2 Monitor
Logic
Watchdog Transition
Detector
WP
Data
Register
Command
Decode &
Control
Logic
V
CC
Threshold
Reset logic
Block Lock Control
The X40626 combines four popular functions, Power-on
Reset Control, Watchdog Timer, Dual Supply Voltage
Supervision, and Serial EEPROM Memory in one pack-
age. This combination lowers system cost, reduces
board space requirements, and increases reliability.
Applying power to the device activates the power on
reset circuit which holds RESET active for a period of
time. This allows the power supply and oscillator to stabi-
lize before the processor can execute code.
The Watchdog Timer provides an independent protection
mechanism for microcontrollers. When the microcontrol-
ler fails to restart a timer within a selectable time-out
interval, the device activates the RESET signal. The user
selects the interval from three preset values. Once
selected, the interval does not change, even after cycling
the power.
The device’s low V
CC
detection circuitry protects the
user’s system from low voltage conditions, resetting the
system when V
CC
falls below the set minimum V
CC
trip
point. RESET is asserted until V
CC
returns to proper
+
V
TRIP2
-
V2FAIL
Watchdog
Timer Reset
Protect Logic
RESET
Status
Register
Reset &
Watchdog
Timebase
SDA
SCL
S0
S1
64KB
EEPROM
Array
V
CC
V
TRIP
+
-
Power on and
Low Voltage
Reset
Generation
REV 1.1.15 2/11/04
www.xicor.com
Characteristics subject to change without notice.
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XICOR [ XICOR INC. ]
