Changhong Electric 21NF55, Руководство по обслуживанию, Страница: 29 / 83

SERVICE MANUAL
27
Fig.14 Functional Diagram
1.4 Electronic switch circuit HEF4053
Triple 2-channel Analog
Multiplexer/Demultiplexer
1). Description
The HEF4053 is a triple 2 -channel analog
multiplexer/demultiplexer with a common enable
input (
E
). Each multiplexer/demultiplexer has two
indepen-
dent inputs/outputs (Y
0
and Y
1
), a common
input/output (Z), and select inputs (Sn). Each also
contains two -bidirectional analog switches, each
with one side connected to an independent
input/output (Y
0
and Y
1
) and the other side
connected to a common input/output (Z).
With (
E
) LOW, one of the two switches is selected
(low impedance ON-state) by Sn. With
E
HIGH, all switches are in the high impedance
OFF-state, independent of S
A
to S
C
.
V
DD
and V
SS
are the supply voltage connections
for the digital control i nputs (S
A
to S
C
and
E
).
The V
DD
to V
SS
range is 3 to 15V.The analog
inputs/outputs (Y
0
, Y
1
and Z) can swing
between V
DD
as a positive limit and V
EE
as a
negative limit. V
DD
-V
EE
may not exceed 15 V.
For operation as a digital
multiplexer/demultiplexer, V
EE
is connected to
V
SS
(typically ground).
2). Block Diagram