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X4003 Datasheet, PDF (1/18 Pages) Xicor Inc. – CPU Supervisor | |||
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X4003/X4005
CPU Supervisor
FEATURES
⢠Selectable watchdog timer
âSelect 200ms, 600ms, 1.4s, off
⢠Low VCC detection and reset assertion
âFive standard reset threshold voltages
nominal 4.62V, 4.38V, 2.92V, 2.68V, 1.75V
âAdjust low VCC reset threshold voltage using
special programming sequence
âReset signal valid to VCC = 1V
⢠Low power CMOS
â12µA typical standby current, watchdog on
â800nA typical standby current watchdog off
â3mA active current
⢠400kHz I2C interface
⢠1.8V to 5.5V power supply operation
⢠Available packages
â8-lead SOIC
â8-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 deviceâs low VCC detection circuitry protects the
userâs system from low voltage conditions, resetting the
system when VCC falls below the minimum VCC trip
point. RESET/RESET is asserted until VCC returns to
proper operating level and stabilizes. Five industry stan-
dard VTRIP thresholds are available; however, Xicorâs
unique circuits allow the threshold to be reprogrammed
to meet custom requirements, or to ï¬ne-tune the thresh-
old for applications requiring higher precision.
WP
SDA
SCL
VCC
Watchdog Transition
Detector
Data
Register
Command
Decode &
Control
Logic
VCC Threshold
Reset logic
Control
Register
+
VTRIP
-
Watchdog
Timer Reset
Reset &
Watchdog
Timebase
Power on and
Low Voltage
Reset
Generation
RESET (X4003)
RESET (X4005)
REV 1.1.3 4/30/02
www.xicor.com
Characteristics subject to change without notice. 1 of 18
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