Eight-Input Multiplexer 1820-0615; Quad 2-Input Multiplexer 1820-0616 - HP 5340A Operating And Service Manual

Model 5340A
Theory of Operation
4-51. Eight-lnput Multiplexer 1820-0615
4-52. The 1820-0615 (Figure 4-23) selects one-bit of output data from eight inputs. The unit has
complementary outputs, and a n enable input (low activates the multiplexer).
line inactive, the multiplexer output
less of the input states. The logic operation is shown in the truth table.
Figure 4-23. Eight-Input Multiplexer 1820-0615

4-53. Quad 2-Input Multiplexer 1820-0616

4-54. The 1820-0616 (Figure 4-24) consists of four 2-input multiplexers with common input
select logic, common active low enable and active high outputs. This allows four bits of data to be
switched in parallel to the'appsopriate outputs from four 2-bit data sources. When the enable
input is high (inactive), all outputs are held low. When the S input is high, the I l a , Ilb, Ilc, and
I l d inputs are transferred t6 $he Za, Zb, Zc, and Zd outputs respectively. The transfer takes
place without polarity inversion. For example, if S is high and Ila is low, then Za will be low,
conversely if I l a is high1 (with
appear at the Z
outputs.
4-16
(Z)
is low and the complementary output (Z) is high regard-
Za
then will go high. When
With the enable
is low, the I0 outputs will