BUY 74LS121 https://www.utsource.net/itm/p/928050.html
QUAD 3-STATE BUFFERS
Description: Dual Monostable Multivibrator Features: High-Speed Performance: tpd = 8.3 ns (typical) at VCC = 5.0 V Low Power Consumption: ICC = 4 μA (max) at Ta = 25°C Wide Operating Voltage Range: VCC (opr) = 2.0 to 6.0 V Outputs Source/Sink 24 mA Symmetrical Output Impedance: |IOH| = IOL = 24 mA (min) Outputs Can Be Disconnected From VCC and VEE Schmitt Trigger Inputs Input Clamping Diodes Standardized, Symmetrical Output Characteristics Meets All Requirements of JEDEC Tentative Standard No. 13B, “Standard Specifications for Description of ‘B’ Series CMOS Devices” Applications: Pulse Generation Time Delay Generation Pulse Width Modulation Pulse Position Modulation Sequential Timing Waveform Generation (For reference only)