Absolute Maximum Ratings:
Supply Voltage: 7V
Input Voltage: 5.5V
Operating Free Air Temperature: 0oC to +70oC
Storage Temperature Range: -65oC to +150oC
These Schottky-clamped circuits are designed to be used
in high-performance memory-decoding or data-routing
applications, requiring very short propagation delay times.
In high-performance memory systems these decoders can
be used to minimize the effects of system decoding. When
used with high-speed memories, the delay times of these
decoders are usually less than the typical access time of
the memory. This means that the effective system delay
introduced by the decoder is negligible.
The DM74LS138 decodes one-of-eight lines, based upon
the conditions at the three binary select inputs and the
three enable inputs. Two active-low and one active-high
enable inputs reduce the need for external gates or inverters when expanding. A 24-line decoder can be implemented with no external inverters, and a 32-line decoder requires only one inverter. An enable input can be used as
a data input for demultiplexing applications.