鈩?/div>
protection
鈥?400kHz 2-wire interface
鈥?2.7V to 5.5V power supply operation
鈥?Available packages
鈥?-lead SOIC
鈥?-lead TSSOP
DESCRIPTION
The X4283/85 combines 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 require-
ments, 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 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鈥檚 low V
CC
detection circuitry protects the
user鈥檚 system from low voltage conditions, resetting
the system when V
CC
falls below the set minimum V
CC
trip point. RESET/RESET is asserted until V
CC
returns
to proper operating level and stabilizes. Four industry
standard Vtrip thresholds are available, however, Inter-
sil鈥檚 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
WP
Data
Register
Command
Decode &
Control
Logic
V
CC
Threshold
Reset logic
Block Lock Control
Protect Logic
Status
Register
EEPROM Array
8Kb 4Kb 4Kb
RESET (X4283)
RESET (X4285)
Watchdog
Timer Reset
SDA
SCL
S0
S1
Reset &
Watchdog
Timebase
V
CC
V
TRIP
+
-
Power-on and
Low Voltage
Reset
Generation
Kb=Kilobyte
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-352-6832
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Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright Intersil Americas Inc. 2005. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.