ZSCT1555

These ZSCT1555 devices are precision timing circuits for generation of accurate time delays or oscillation. Advanced circuit design means that these ZSCT1555 devices can operate from a single battery cell with the minimum of quiescent current.In monostable mode time delays are controlled by a single resistor and capacitor network. In astable mode the frequency and duty cycle can be accurately and independently controlled with two external resistors and one capacitor. The threshold and trigger levels are normally set as a proportion of V_CC by internal resistors. These levels of ZSCT1555 can be programmed by the use of the control input pin. When the trigger input reduces to a value below the trigger level, the flip-flop is set and the output goes high. With the trigger input above the trigger level and the threshold input above the threshold level, the flip-flop is resetand the output goes low. The reset pin has priority over all the other inputs and is used to start new timing cycles. A low on the reset input causes the flip-flop to reset forcing the output low. Whenever the output is forced low then the internal discharge transistor is turned on.