X4003, X4005
®
Data Sheet
May 11, 2006
FN8113.1
DESCRIPTION
CPU Supervisor
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.
FEATURES
• Selectable watchdog timer
—Select 200ms, 600ms, 1.4s, off
• Low V detection and reset assertion
CC
—Five standard reset threshold voltages
nominal 4.62V, 4.38V, 2.92V, 2.68V, 1.75V
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.
—Adjust low V reset threshold voltage using
CC
special programming sequence
—Reset signal valid to V = 1V
CC
• Low power CMOS
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.
—12µA typical standby current, watchdog on
—800nA typical standby current watchdog off
—3mA active current
2
• 400kHz I C interface
• 1.8V to 5.5V power supply operation
• Available packages
—8 Ld SOIC
—8 Ld MSOP
• Pb-free plus anneal available (RoHS compliant)
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 trip
CC
CC
point. RESET/RESET is asserted until V
returns to
CC
proper operating level and stabilizes. Five industry stan-
dard V thresholds are available; however, Intersil’s
TRIP
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 Transition
Detector
Watchdog
Timer Reset
WP
RESET (X4003)
RESET (X4005)
Data
Register
SDA
Control
Register
Command
Decode &
Control
Reset &
Watchdog
Timebase
SCL
Logic
V
Threshold
CC
Reset logic
Power-on and
Low Voltage
V
Reset
Generation
+
-
CC
V
TRIP
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2005-2006. All Rights Reserved
1
All other trademarks mentioned are the property of their respective owners.