XL551 Datasheet | XINLUDA

description The XL551 is a monolithic timing circuit fabricated using Lin CMOS ™process. The timer is fully patible with CMOS, TTL, and MOS logic and operates at frequencies up to 2 MHz. pared to the XL555 timer, this device uses smaller timing capacitors because of its high input impedance. 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 XL555, the XL551 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. If TRIG is above the trigger level and the threshold input (THRES) is above the threshold level, the flip-flop is reset and the output is low. The reset input (RESET) can override all other inputs and can be used to initiate a new timing cycle. If RESET is low, the flip-flop is reset and the output is low. Whenever the output is low, a low-impedance path is provided between DISCH and GND. All unused inputs should be tied to an appropriate logic level to prevent false triggering. While the CMOS output is capable of sinking over 100 m A and sourcing over 10 m A, the XL551 exhibits greatly reduced supply-current spikes during output transitions. This minimizes the need for the large decoupling capacitors required by the XL555. The XL551C is characterized for operation from 0 °C to 70°C. XL551 SOP8 FUNCTION TABLE RESET VOLTAGE † TRIGGER THRESHOLD VOLTAGE † VOLTAGE † OUTPUT DISCHARGE SWITCH <MIN Irrelevant Irrelevant Low On >MAX <MIN Irrelevant High Off >MAX >MAX >MAX Low On >MAX >MAX <MIN As previously established † For conditions shown as MIN or MAX, use the appropriate value specified under electrical characteristics. XL551 chip information This chip, when...