Description
TheTL7700Aseriesaremonolithicintegratedcircuit supplyvoltagesupervisorsspecificallydesi-gnedfor use as reset controllers in microcomputer and microprocessorsystems. During power-upthe device tests the supply voltage and keeps the RESET and 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.To ensurethatthe microcomputersystemhasreset,theTL7700Athen initiatesaninternal timedelaythatdelaysthereturnof the resetoutputs to theirinactivestates.Since thetimedelay for most microcomputersandmicroprocessorsis intheorder of several machine cycles, the device internal time delayis determinedby an externaltime delay is determined by an externalcapacitorconnectedto the CT input (pin 3). td = 1.3 x 104 x CT Where : CT is in farads (F) and td inseconds (s). In addition, when the supply voltage drops below the nominal value, the outputs will be active until the supply voltage returns to the nominal value. An externalcapacitor(typically0.1µF)mustbeconnected to the REF output (pin 1) to reduce the influence of fast transientsin the supply voltage. The TL7700AIseries is characterized for operation from – 25oC to 85oC ; theTL7700ACseries is characterized from 0oC to 70oC. D SO8 ORDERING NUMBERS Temperature Range Minidip S08 0 to 70oC TL77XXACP TL77XXACD -25 to 85oC TL77XXAIP TL77XXAID