REV 1.1.2 5/29/01
Characteristics subject to change without notice.
1 of 20
www.xicor.com
4K
X5043/X5045
512 x 8 Bit
CPU Supervisor with 4K SPI EEPROM
FEATURES
Selectable time out watchdog timer
Low V
CC
detection and reset assertion
—Five standard reset threshold voltages
—Re-program low V
using special programming sequence.
—Reset signal valid to V
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
—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
—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
CC
reset threshold voltage
CC
= 1V
memory
DESCRIPTION
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.
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
user’s system from low voltage conditions, resetting
the system when V
CC
falls below the minimum V
trip point. RESET/RESET is asserted until V
to proper operating level and stabilizes. Five industry
standard V
TRIP
thresholds are available, however,
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.
CC
detection circuitry protects the
CC
CC
returns
BLOCK DIAGRAM
Watchdog
Timer Reset
Data
Register
Command
Decode &
Control
Logic
SI
SO
SCK
CS/WDI
V
CC
Reset &
Watchdog
Timebase
Power on and
Low Voltage
Generation
V
TRIP
+
-
RESET/RESET
Reset
Status
Register
Protect Logic
1Kbits
1Kbits
2Kbits
E
Watchdog Transition
Detector
WP
X5043 = RESET
X5045 = RESET
V
CC
Threshold
Reset Logic