SN75ALS121

ą SN75ALS121 DUAL LINE DRIVER ą SLLS030A − D1334, SEPTEMBER 1987 − REVISED AUGUST 1989 Permits Digital Data Transmission Over Coaxial Cable, Strip Line, or Twisted Pair Operates With 50-Ω to 500-Ω Transmission Lines TTL Compatible With 5-V Supply 2.4-V Output at IOH = −75 mA Uncommitted Emitter-Follower Output Structure for Party-Line Operation IMPACT Low-Power Schottky Technology Improved Replacement for the SN75121 and Signetics 8T13 Glitchless Power Up/Power Down Short-Circuit Protection AND-OR Logic Configuration High Speed . . . Maximum Propagation Delay Time of 14 ns at CL = 15 pF description The SN75ALS121 dual line driver is designed for digital data transmission over lines having impedances from 50 to 500 Ω. It is compatible with standard TTL logic and supply voltage levels. D OR N PACKAGE (TOP VIEW) 1A 1B 1C 1D 1E 1F 1Y GND 1 2 3 4 5 6 7 8 16 VCC 15 2F 14 2E 13 2D 12 2C 11 2B 10 2A 9 2Y NOT RECOMMENDED FOR NEW DESIGN FUNCTION TABLE INPUTS OUTPUT A BC DE F Y H HH HX X X XX XHH All other input combinations H = high level, L = low level, X = irrelevant H H L The low-impedance emitter-follower outputs drive terminated lines such as coaxial cable, strip line, or twisted pair. Having the outputs uncommitted allows wired-OR logic to be performed in party-line applications. Output short-circuit protection is provided by an internal clamping network that turns on when the output voltage drops below approximately 1.5 V. All inputs are in c...