X4003 Datasheet, PDF (1/17 Pages) Xicor Inc. – CPU Supervisor

®
Data Sheet
X4003, X4005
March 15, 2005
FN8113.0
CPU Supervisor
FEATURES
• Selectable watchdog timer
—Select 200ms, 600ms, 1.4s, off
• Low V_CC detection and reset assertion
—Five standard reset threshold voltages
nominal 4.62V, 4.38V, 2.92V, 2.68V, 1.75V
—Adjust low V_CC reset threshold voltage using
special programming sequence
—Reset signal valid to V_CC = 1V
• Low power CMOS
—12µA typical standby current, watchdog on
—800nA typical standby current watchdog off
—3mA active current
• 400kHz I²C interface
• 1.8V to 5.5V power supply operation
• Available packages
—8-lead SOIC
—8-lead MSOP
BLOCK DIAGRAM
DESCRIPTION
These devices combine three popular functions,
Power-on Reset Control, Watchdog Timer, and Supply
Voltage Supervision. 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 oscilla-
tor to stabilize before the processor can execute code.
The Watchdog Timer provides an independent
protection mechanism for microcontrollers. When the
microcontroller fails to restart a timer within a select-
able 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.
WP
SDA
SCL
V_CC
Watchdog Transition
Detector
Data
Register
Command
Decode &
Control
Logic
V_CC Threshold
Reset logic
Control
Register
+
V_TRIP
-
Watchdog
Timer Reset
Reset &
Watchdog
Timebase
Power-on and
Low Voltage
Reset
Generation
RESET (X4003)
RESET (X4005)
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
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