X4323, X4325
®
32K, 4K x 8 Bit
Data Sheet
March 29, 2005
FN8122.0
DESCRIPTION
CPU Supervisor with 32K EEPROM
The X4323/5 combines four popular functions, Power-
on Reset Control, Watchdog Timer, Supply Voltage
Supervision, and Serial EEPROM Memory in one pack-
age. This combination lowers system cost, reduces
board space requirements, and increases reliability.
FEATURES
• Selectable watchdog timer
• Low V detection and reset assertion
CC
—Four standard reset threshold voltages
—Adjust low V reset threshold voltage using
CC
Applying power to the device activates the power-on
reset circuit which holds RESET/RESET active for a
period of time. This allows the power supply and oscilla-
tor to stabilize before the processor can execute code.
special programming sequence
—Reset signal valid to V = 1V
CC
• Low power CMOS
—<20µA max standby current, watchdog on
—<1µA standby current, watchdog off
—3mA active current
• 32Kbits of EEPROM
—64-byte page write mode
—Self-timed write cycle
—5ms write cycle time (typical)
• Built-in inadvertent write protection
—Power-up/power-down protection circuitry
—Block Lock (1, 2, 4, 8 pages, all, none)
• 400kHz 2-wire interface
• 2.7V to 5.5V power supply operation
• Available packages
—8-lead SOIC
The Watchdog Timer provides an independent protec-
tion mechanism for microcontrollers. When the micro-
controller fails to restart a timer within a selectable time
out interval, the device activates the RESET/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
detection circuitry protects the
CC
user’s system from low voltage conditions, resetting the
system when V falls below the set minimum V trip
CC
CC
point. RESET/RESET is asserted until V
returns to
CC
proper operating level and stabilizes. Four industry
standard V thresholds are available, however, Inter-
TRIP
—8-lead TSSOP
sil’s unique circuits allow the threshold to be repro-
grammed to meet custom requirements or to fine-tune
the threshold for applications requiring higher precision.
BLOCK DIAGRAM
Watchdog Transition
Detector
Watchdog
Timer Reset
WP
Protect Logic
RESET (X4323)
RESET (X4325)
Data
Register
SDA
Status
Register
EEPROM Array
Command
Reset &
Watchdog
Timebase
SCL
Decode &
Control
Logic
S0
S1
VCC Threshold
Reset logic
Power-on and
+
-
Low Voltage
VCC
Reset
Generation
VTRIP
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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