Description
These devices are precision timing circuits capable ofproducing accurate time delays or oscillation. In thetime-delay or mono-stable mode of operation,thetimed interval is controlled by a single externalresistor and capacitor network. In the a-stable modeof operation,the frequency and duty cycle can becontrolled independently with two external resistorsand a single external capacitor.
The threshold and trigger levels normally are two-thirds and one-third,respectively,of vcc: Theselevels can be altered by use of the control-voltageterminal. When the trigger input falls below the triggerlevel, the flip-flop is set, and the output goes high. lfthe trigger input is above the trigger level and thethreshoid input is above the threshold level, the flip-flop is reset and the output is low.The reset (RESET)input can override all other inputs and can be used toinitiate a new timing cycle. When RESET goes low,the flip-flop is reset,and the output goes low. Whenthe output is low,a low-impedance path is providedbetween discharge (DISCH) and ground.
The output circuit is capable of sinking or sourcingcurrent up to 200mAOperation is specified forsupplies of 5 V to 15 v. With a 5-V supply,outputlevels are compatible with TTL inputs.




