TL7700 A Series
April1993
SUPPLY VOLTAGE SUPERVISORS
.POWER-ON RESET GENERATOR
.AUTOMATIC RESET GENERATION AFTER
VOLTAGEDROP
.WIDE SUPPLY VOLTAGE RANGE ... 3V TO
18V
.PRECISIONVOLTAGESENSOR
.TEMPERATURE-COMPENSATED VOLTAGE
REFERENCE
.TRUE AND COMPLEMENT RESET OUTPUTS
.EXTERNALLYADJUSTABLEPULSE WIDTH N
Minidip
DESCRIPTION
TheTL7700Aseriesaremonolithicintegratedcircuit
supplyvoltagesupervisorsspecificallydesi-gnedfor
use as reset controllers in microcomputer and mi-
croprocessorsystems. During power-upthe device
teststhesupplyvoltageand keepsthe RESETand
RESET outputs active (high and low, respectively)
as long as the supply voltage has not reached its
nominal voltage value. Taking RESIN low has the
sameeffect.Toensurethatthemicrocomputersys-
temhasreset,theTL7700Atheninitiatesaninternal
timedelaythatdelaysthereturnoftheresetoutputs
totheirinactivestates.Sincethetime delayformost
microcomputersandmicroprocessorsis intheorder
of several machine cycles, the device internal time
delayis determinedby anexternaltime delayis de-
termined by an externalcapacitorconnectedto the
CTinput(pin 3).
td= 1.3 x 104xC
T
Where : CTis in farads(F) andtdinseconds (s). In
addition,when the supply voltagedrops below the
nominal value, the outputs will be active until the
supply voltage returnsto the nominal value.An ex-
ternalcapacitor(typically0.1µF)mustbeconnected
to the REF output (pin 1) to reduce the influenceof
fasttransientsin the supplyvoltage.
The TL7700AIseries is characterizedfor operation
from– 25oCto85
o
C ;the TL7700ACseries is char-
acterizedfrom0oCto70
o
C.
D
SO8
ORDERING NUMBERS
Temperature Range Minidip S08
0to70
o
C TL77XXACP TL77XXACD
-25 to 85oC TL77XXAIP TL77XXAID
PIN CONNECTION (top view)
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