EL4332C
Triple 2:1 300 MHz Mux-Amp AV =2
used, a 220Ω to 330Ω resistor to the -5.2V rail would
have the same effect.
Expanding the Multiplexer
In Figure 4, a 3:1 multiplexer circuit is shown. The
expansion to more inputs is very straight forward. Since
the EL4332C has a fixed gain of 2, interstage attenuators
may be required as shown in Figure 3. The truth table for
the 3:1 multiplexer select lines is:
X
Y
0
0
0
1
1
X
Mux Output
R3, G3, B3
R2, G2, B2
R1, G1, B1
When interstage attenuators are used, the values should
be kept down in the region of 50Ω–300Ω. This is to pre-
vent a combination of circuit board stray capacitance
and the EL4332C’s input capacitance forming a signifi-
cant pole. For example, if instead of 100Ω as shown,
resistors of 1 kΩ had been used, and assuming 3 pF of
stray and 3 pF of input capacitance, a pole would be
formed at about 53 MHz.
Figure 4. Typical Connection for a 3:1 Component Video Multiplexer
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