鈩?/div>
protection
鈥擨n circuit programmable ROM mode
鈥?2MHz SPI interface modes (0,0 & 1,1)
鈥?Minimize EEPROM programming time
鈥?2-byte page write mode
鈥擲elf-timed write cycle
鈥?ms write cycle time (typical)
鈥?2.7V to 5.5V and 4.5V to 5.5V power supply
operation
鈥?Available packages
鈥?-lead PDIP, 14-lead SOIC
BLOCK DIAGRAM
Watchdog Transition
Detector
WP
SI
SO
SCK
CS/WDI
Data
Register
Command
Decode &
Control
Logic
V
CC
Threshold
Reset logic
Protect Logic
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 sys-
tem 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 microcon-
troller 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 minimum V
CC
trip point. RESET/RESET is asserted until V
CC
returns
to proper operating level and stabilizes. Five industry
standard V
TRIP
thresholds are available, however,
Intersil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.
Watchdog
Timer Reset
RESET/RESET
Status
Register
EEPROM Array
16Kbits
16Kbits
32Kbits
Reset &
Watchdog
Timebase
X5643 = RESET
X5645 = RESET
V
CC
V
TRIP
+
-
Power-on and
Low Voltage
Reset
Generation
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.