Active 74LS XOR — 23 ns propagation delay, 4.75-5.25 V supply
The Texas Instruments 74LS86PC is an active-production quad 2-input XOR gate from the 74LS low-power Schottky family. It integrates four independent exclusive-OR gates in a single 14-pin DIP, each with two inputs, suited for digital comparison, parity generation, and controlled inversion in through-hole designs. The 23 ns maximum propagation delay at 5 V with a 50 pF load sets the data-rate ceiling — for a 5 V rail, this is the timing budget the downstream logic sees.
Supply rails and logic thresholds — 0.8 V low, 2 V high
Input logic thresholds are specified at 0.8 V maximum for a low level and 2 V minimum for a high level, referenced to the 5 V nominal rail. This 1.2 V noise margin between the thresholds and the supply rails provides standard TTL compatibility — a 74LS output driving a 74LS input has guaranteed noise immunity across the 0-70°C range. The 15 mA quiescent current is the total for all four gates when unloaded — each output sourcing or sinking adds to the supply draw. At 8 mA sink per output with all four gates low, the total is 15 mA + (4 × 8 mA) = 47 mA, which stays within the 5 V rail's typical 100 mA budget for a small logic cluster.