SLVS019D - OCTOBER 1987 - REVISED OCTOBER 1995
The TL7770 is a monolithic integrated circuit system supervisor designed for use as a reset controller in microcomputer and microprocessor power supply systems. This device contains two independent supply-voltage supervisors that monitor the supplies for overvoltage and under-voltage conditions at the VSO and VSU terminals respectively. When VCC attains the minimum voltage of 1 V during power-up, the RESET\ output becomes active (low). As VCC approaches 3.5 V, the delay timer function activates latching RESET and RESET\ active (high and low, respectively) for a time delay, td, after system voltages have achieved normal levels. Above VCC = 3.5 V, taking RESIN\ low activates the time delay function, RESET and RESET\, during normal system voltage levels. To ensure that the microcomputer system has reset, the outputs remain active until the voltage at VSU exceeds the threshold value VIT+ for a time delay, td, which is determined by an external timing capacitor such that:
td no map 20 × 103 × capacitance
where td is in seconds and capacitance is in farads.
The overvoltage-detection circuit is programmable for a wide range of user designs. During an overvoltage condition, an internal silicon-controlled rectifier (SCR) is triggered, providing 250-mA peak instantaneous current and 25-mA continuous current to the SCR gate drive terminal, which can drive an external high-current SCR gate or an overvoltage warning circuit.
The TL7770C is characterized for operation from 0°C to 70°C. The TL7770M series is characterized for operation from - 55°C to 125°C. The TL7770Q series is characterized for operation from - 40°C to 125°C.
View more information about generic part numbers:TL7770-12, TL7770-12M, TL7770-15, TL7770-15M, TL7770-5, TL7770-5M
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