HCF4097B

7/10

APPLICATION INFORMATION

In applications where separate power sources are

effective external load). This provision avoids

permanent current flow or clamp action on the

from the HCF4097B.

When switching from one address to another,

some of the ON periods of the channels of the

multiplexers will overlap momentarily, which may

be objectionable in certain applications. Also,

when a channel is turned ON or OFF by an

address input, there is a momentary conductive

some charge from any capacitor connected to the

input or output of the channel. The inhibit input

turning on a channel will similarly dump some

The amount of charge dumped is mostly a

the input or output of the channel will lose 3-4% of

its voltage at the moment the channel turns ON or

OFF.

This

loss

of

voltage

is

essentially

independent of the address or inhibit signal

transition time, if the transition time is less than 1-

2 ms. When the inhibit signal turns a channel off,

is a slight rise in the channel voltage level (65 mV

typ.) due to the capacitance coupling from inhibit

input to channel input or output. Address input

also couple some voltage steps onto the channel

signal levels.

In certain applications, the external load-resistor

switch current flows into the transmission gate

inputs, the voltage drop across the bidirectional

values

shown

in

ELECTRICAL

terminal 1 on the HCF4097B.

TEST CIRCUIT