1
FN8118.3
X4043, X4045
4k, 512 x 8 Bit
CPU Supervisor with 4kbit EEPROM
FEATURES
• Selectable watchdog timer
•Low V
CC
detection and reset assertion
—Five standard reset threshold voltages
—Adjust low V
CC
reset threshold voltage using
special programming sequence
—Reset signal valid to V
CC
= 1V
• Low power CMOS
—<20µA max standby current, watchdog on
—<1µA standby current, watchdog OFF
—3mA active current
• 4kbits of EEPROM
—16-byte page write mode
—Self-timed write cycle
—5ms write cycle time (typical)
• Built-in inadvertent write protection
—Power-up/power-down protection circuitry
—Protect 0, 1/4, 1/2, all or 16, 32, 64 or 128 bytes
of EEPROM array with Block Lock
™
protection
• 400kHz 2-wire interface
• 2.7V to 5.5V power supply operation
• Available packages
—8 Ld SOIC
—8 Ld MSOP
—8 Ld PDIP
• Pb-free plus anneal available (RoHS compliant)
DESCRIPTION
The X4043/45 combines four popular functions,
Power-on Reset Control, Watchdog Timer, Supply
Voltage Supervision, and Block Lock Protect Serial
EEPROM Memory in one package. This combination
lowers system cost, reduces board space require-
ments, and increases reliability.
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.
The Watchdog Timer provides an independent protection
mechanism for microcontrollers. When the microcon-
troller 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
CC
detection circuitry protects the
user’s system from low voltage conditions, resetting the
system when V
CC
falls below the minimum V
CC
trip
point. RESET
/RESET is asserted until V
CC
returns to
proper operating level and stabilizes. Five industry stan-
dard V
TRIP
thresholds are available, however, Intersil’s
unique circuits allow the threshold to be reprogrammed
to meet custom requirements or to fine-tune the thresh-
old for applications requiring higher precision.
BLOCK DIAGRAM
Watchdog
Timer Reset
Data
Register
Command
Decode &
Control
Logic
SDA
SCL
V
CC
Reset &
Watchdog
Timebase
Power-on and
Generation
V
TRIP
+
-
RESET (X4043)
Reset
Low Voltage
Status
Register
Protect Logic
EEPROM Array
Watchdog Transition
Detector
WP
V
CC
Threshold
Reset logic
Block Lock Control
2Kbits 1Kb 1Kb
RESET (X4045)
Data Sheet December 9, 2015
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC
2005, 2006, 2015. All Rights Reserved
Intersil (and design) and XDCP are trademarks owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
