the tlc555 is a monolithic timing circuit fabricated using the ti lincmos process. the timer is fully compatible with cmos ttl and mos logic and operates at frequencies up to 2mhz. because of its high input impedance this device uses smaller timing capacitors than those used by the ne555. as a result more accurate time delays and oscillations are possible. power consumption is low across the full range of power supply voltage. like the ne555 the tlc555 has a trigger level equal to approximately one-third of the supply voltage and a threshold level equal to approximately two-thirds of the supply voltage. these levels can be altered by use of the control voltage terminal (cont). when the trigger input (trig) falls below the trigger level the flip-flop is set and the output goes high. view all in datasheet