Bipolar buffer, SN74LS241N, Texas Instruments
The SN74LS241N octal buffer and line driver is designed specifically to improve both the performance and density of three-state memory address driver, clock driver, and bus-oriented receiver and transmitter. The designer has a choice of selected combinations of inverting and non-inverting output, symmetrical, active-low output-control (G) input, and complementary output-control (G and G) input. This device features high fan-out, improved fan-in, and 400-mV noise margin. The SN74LS241N device can be used to drive terminated line down to 133 Ω.
Features
 - PNP Inputs Reduce DC Loading 
 - Hysteresis at Inputs Improves Noise Margins