TL7700A

TheTL7700Aseriesaremonolithicintegratedcircuit supplyvoltagesupervisorsspecificallydesi-gnedfor use as reset controllers in microcomputer and microprocessor systems. During power-up the 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 timedelay that delays the returnof the resetoutputs  to their inactivestates.Since the timedelay for most microcomputersandmicroprocessorsis in theorder of several machine cycles, the device internal time delayis determinedby an external time delay is determined by an externalcapacitor connected to the CT input (pin 3).
t_d = 1.3 x 10⁴ x C_T
Where : CT is in farads (F) and td in seconds (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( typically0.1mF)mustbeconnected to the REF output (pin 1) to reduce the influence of fast transients in the supply voltage.

The TL7700AI series is characterized for operation from 25oC to85oC ; the TL7700ACseries is characterized from 0^oC to70^oC.