4K
512 x 8 Bit
X5043/X5045
CPU Supervisor with 4K SPI EEPROM
DESCRIPTION
FEATURES
• Selectable time out watchdog timer
• Low V detection and reset assertion
These devices combine 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 requirements, and
increases reliability.
CC
—Five standard reset threshold voltages
—Re-program low V reset threshold voltage
CC
using special programming sequence.
—Reset signal valid to V = 1V
CC
• Long battery life with low power consumption
—<50µA max standby current, watchdog on
—<10µA max standby current, watchdog off
—<2mA max active current during read
• 2.7V to 5.5V and 4.5V to 5.5V power supply
versions
• 4Kbits of EEPROM–1M write cycle endurance
• Save critical data with Block Lock™ memory
—Protect 1/4, 1/2, all or none of EEPROM array
• Built-in inadvertent write protection
—Write enable latch
—Write protect pin
• 3.3MHz clock rate
• Minimize programming time
—16-byte page write mode
—Self-timed write cycle
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 oscil-
lator to stabilize before the processor executes code.
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 minimum V
CC
CC
trip point. RESET/RESET is asserted until V
returns
CC
—5ms write cycle time (typical)
• SPI modes (0,0 & 1,1)
• Available packages
—8-lead MSOP, 8-lead SOIC, 8-pin PDIP
—14-lead TSSOP
to proper operating level and stabilizes. Five industry
standard V thresholds are available, however,
TRIP
Xicor’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/RESET
SI
Data
Register
Status
Register
SO
X5043 = RESET
X5045 = RESET
Command
Decode &
Control
Reset &
Watchdog
Timebase
SCK
1Kbits
1Kbits
CS/WDI
Logic
V
Threshold
CC
2Kbits
Reset Logic
Power on and
Low Voltage
Reset
V
+
-
CC
V
Generation
TRIP
Characteristics subject to change without notice. 1 of 20
REV 1.1.2 5/29/01
www.xicor.com