1-of-8 Decoder

The \x92FCT138T devices are 1-of-8 decoders. These devices accept three binary weighted inputs (A0, A1, A2) and, when enabled, provide eight mutually exclusive active-low outputs (O\0\x96O\7). The \x92FCT138T devices feature three enable inputs: two active low (E\1, E\2) and one active high (E3 ).

All outputs are high unless E\1 and E\2 are low and E3 is high. This multiple-enable function allows easy parallel expansion of the device to a 1-of-32 (five lines to 32 lines) decoder with just four \x92FCT138T devices and one inverter.

These devices are fully specified for partial-power-down applications using Ioff. The Ioff circuitry disables the outputs, preventing damaging current backflow through the device when it is powered down.