. Electronic Components Datasheets 74ls221 free download

File name 74ls221.pdf

SN54/74LS221 DUAL MONOSTABLE MULTIVIBRATORS WITH SCHMITT-TRIGGER INPUTS Each multivibrator of the LS221 features a negative-transition-triggered DUAL MONOSTABLE input and a positive-transition-triggered input either of which can be used as MULTIVIBRATORS an inhibit input. WITH SCHMITT-TRIGGER INPUTS Pulse triggering occurs at a voltage level and is not related to the transition time of the input pulse. Schmitt-trigger input circuitry for B input allows LOW POWER SCHOTTKY jitter-free triggering for inputs as slow as 1 volt / second, providing the circuit with excellent noise immunity. A high immunity to VCC noise is also provided by internal latching circuitry. Once triggered, the outputs are independent of further transitions of the inputs and are a function of the timing components. The output pulses can be J SUFFIX terminated by the overriding clear. Input pulse width may be of any duration CERAMIC relative to the output pulse width. Output pulse width may be varied from 35 CASE 620-09 16 nanoseconds to a maximum of 70 s by choosing appropriate timing 1 components. With Rext = 2.0 k and Cext = 0, a typical output pulse of 30 nanoseconds is achieved. Output rise and fall times are independent of pulse length. Pulse width stability is achieved through internal compensation and is N SUFFIX virtually independent of VCC and temperature. In most applications, pulse PLASTIC stability will only be limited by the accuracy of external timing components. CASE 648-08 16 Jitter-free operation is maintained over the full temperature and VCC ranges for greater than six decades of timing capacitance (10 pF to 10