Microprocessor
Supervisory Circuits
a
ADM8698/ADM8699
FUNCTIO NAL BLO CK D IAGRAM
FEATURES
Superior Upgrade for ADM698/ ADM699, MAX698/ MAX699
Guaranteed RESET Assertion w ith VCC = 1 V
Low 70 A Supply Current
Precision 4.65 V Voltage Monitor
Pow er OK/ Reset Tim e Delay
ADM8698/
ADM8699
RESET*
V
CC
RESET
GENERATOR
RESET
Watchdog Tim er
Minim um Com ponent Count
4.65V
Perform ance Specified over Tem perature
WATCHDOG
INPUT
WATCHDOG
WATCHDOG
APPLICATIONS
Microprocessor System s
Com puters
TRANSITION DETECTOR
OUTPUT WDO*
WDI*
(1 sec)
Controllers
*WDI (ADM8699 ONLY)
RESET (SOIC ONLY)
WDO (ADM8699 SOIC ONLY)
Intelligent Instrum ents
Autom otive System s
Critical P Pow er Monitoring
TYP ICAL AP P LICATIO N CIRCUIT
+5V
GENERAL D ESCRIP TIO N
T he ADM8698/ADM8699 supervisory circuits provide power
supply monitoring and watchdog timing for microprocessor
systems.
VCC
µP POWER
µP RESET
RESET
T he ADM8698 monitors the 5 V VCC power supply and gener-
ates a RESET pulse during power up, power down and during
low voltage “Brown Out” conditions. T he RESET output is
guaranteed to be functional (logic low) with VCC as low as 1 V.
ADM8698/
ADM8699
µP SYSTEM
WDI
*
I/O LINE
GND
T he ADM8699 features an identical monitoring circuit as in the
ADM8698, plus an additional watchdog timer input to monitor
microprocessor activity. T he RESET output is forced low if the
watchdog input is not toggled within the 1 second watchdog
timeout period.
*ADM8699 ONLY
Both parts are available in 8-pin plastic DIP/SOIC and 16-lead
SOIC packages. T he 16-lead SOIC contains additional out-
puts RESET (without inversion) and Watchdog Output WDO
(ADM8699 only).
REV. 0
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