The IN74ACT139 is identical in pinout to the LS/ALS139, HC/HCT139. The IN74ACT139 may be used as a level converter for interfacing TTL or NMOS outputs to High Speed CMOS inputs.
This device consists of two independent 1-of-4 decoders, each of which decodes a two-bit Address to one-of-four active-low outputs. Active-low Selects are provided to facilitate the demultiplexing and cascading functions. The demultiplexing function is accomplished by using the Address inputs to select the desired device output, and utilizing the Select as a data input.

• TTL/NMOS Compatible Input Levels
• Outputs Directly Interface to CMOS, NMOS, and TTL
• Operating Voltage Range: 4.5 to 5.5 V
• Low Input Current: 1.0 μA; 0.1 μA @ 25°C
• Outputs Source/Sink 24 mA