EL4331C
Triple 2:1 Mux-Amp AV = 1
A demonstration board with this circuit on it is available
from Elantec.
Figure 2. A Bandwidth-Selectable Filter
amplifier output is loaded, to keep the amplifier outputs
damped.
Application Circuit #2
Figure 2 shows a circuit that has either a very wide band-
width, or an 11 MHz low pass response. The EL4331’s
“A” inputs are connected to the one frequency determin-
ing set of components, while the “B” inputs are
connected directly. The A/B select pin therefore selects
the desired bandwidth. This would allow appropriate fil-
tering to clean up noisy low bandwidth video signals
when displaying them on a high quality wide bandwidth
monitor.
Photograph A1 shows a staircase generated by having all
the inputs (sig0 through sig7) connected to a resistive
divider chain, and the select bits were driven by a binary
counter. Photograph A2 shows the glitch between steps
4 and 5; this is the worst glitch since all three banks of
EL4331s are switching together. The magnitude of this
glitch is affected by the timing skew of the select lines,
the physical length of the traces, and the difference in
amplitude of the two signals. This particular circuit was
bread-boarded using EL4331s on their adapter boards
(available from Elantec for those who can not bread-
board with SOICs), and the binary counter was an
'LS163.
Application Circuit #3
Figure 3 shows one of the three channels of a component
video, 8:1 multiplexer. The A/B select pins naturally
allow binary coded addressing—allowing simple micro-
processor or state machine control. Note that each
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