Open-collector hex inverter — 40 mA sink per channel
The SN74LS06N is a hex inverter from Texas Instruments' 74LS family, with each of its six channels capable of sinking up to 40 mA when the output is low — the open-collector stage pulls the output to ground through the load, so the actual voltage swing is set by the pull-up resistor and the supply rail the load connects to. The 20 ns propagation delay at 5 V with a 15 pF load keeps it in the speed class for bus-interface and lamp/relay drive applications where the open-collector output handles the higher voltage or current on the load side.