The MC14558B decodes 4–bit binary coded decimal data dependent on the state of auxiliary inputs, Enable and RBI, and provides an active–high seven–segment output for a display driver.
An auxiliary input truth table is shown, in addition to the BCD to seven–segment truth table, to indicate the functions available with the two auxiliary inputs.
Leading Zero blanking is easily obtained with an external flip–flop in time division multiplexed systems displaying most significant decade first.

• Supply Voltage Range = 3.0 Vdc to 18 Vdc
• Segment Blanking for All Illegal Input Combinations
• Lamp Test Function
• Capability for Suppression of Non–Significant Zeros
• Lamp Intensity Function
• Capable of Driving Two Low–power TTL Loads. One Low–power Schottky TTL Load or Two HTL Loads Over the Rated Temperature Range