The MC74HCT138A is identical in pinout to the LS138. The HCT138A may be used as a level converter for interfacing TTL or
NMOS outputs to High Speed CMOS inputs. The HCT138A decodes a threeâbit Address to oneâofâeight activeâlot outputs. This device features three Chip Select inputs, two activeâlow and one activeâhigh to facilitate the demultiplexing, cascading, and chipâselecting functions. The demultiplexing function is accomplished by using the Address inputs to select the desired
device output; one of the Chip Selects is used as a data input while the other Chip Selects are held in their active states.
Features
⢠Output Drive Capability: 10 LSTTL Loads
⢠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 A
⢠In Compliance with the Requirements Defined by JEDEC Standard
No. 7A
⢠Chip Complexity: 122 FETs or 30.5 Equivalent Gates
⢠PbâFree Packages are Available*
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