The 74HC153; 74HCT153 is a dual 4-input multiplexer. The device features independent
enable inputs (nE) and common data select inputs (S0 and S1). For each multiplexer, the
select inputs select one of the four binary inputs and routes it to the multiplexer output
(nY). A HIGH on E forces the corresponding multiplexer outputs LOW. Inputs include
clamp diodes. This enables the use of current limiting resistors to interface inputs to
voltages in excess of VCC.
The 74F258A has four identical 2-input multiplexers with 3-State
outputs which select 4 bits of data from two sources under control of
a common Select (S) input. The I0n inputs are selected when the
Select input is Low and the I1n inputs are selected when the Select
input is High. Data appears at the outputs in inverted form.
The 74LV251 is a low-voltage Si-gate CMOS device and is pin and
function compatible with 74HC/HCT251.
The 74LV251 is an 8-input multiplexer with 8 binary inputs (I0 to I7), an
output enable input (OE) and three select inputs (S0, S1, S2). One of
the eight binary inputs is selected by the select inputs and is routed to
the outputs (Y, Y). Both outputs are in the high impedance OFF-state
(Z) when the output enable input is HIGH, allowing multiplexer
expansion by tying the outputs.
The 74F257A has four identical 2-input multiplexers with 3-State
outputs which select 4 bits of data from two sources uncer control of
a common Select (S) input. The I0a inputs are selected when the
common Select input is Low and the I1n inputs are selected when
the common Select input is High. Data appears at the outputs in true
non-inverted form from the selected inputs. The 74F257A is the logic
implementation of a 4-pole, 2-position switch where the position of
the switch is determined
