
Propagation Delay Waveform Channel Being
Turned ON (R
L
= 10 K
, C
L
= 50 pF)
Propagation Delay Waveform Channel Being
Turned OFF (R
L
= 300
, C
L
= 50 pF)
APPLICATIONS INFORMATION
In applications where separate power sources are
used todriveV
DD
and thesignal inputs, theV
DD
cur-
rentcapability should exceedV
DD
/R
L
(R
L
= effective
external load).Thisprovisionavoids permanent cur-
rent flow or clamp action on the V
DD
supply when
power
is
applied
or
HCC/HCF4067B
or
HCC/HCF4097B.
Whenswitchingfromone address toanother, some
oftheONperiodsofthechannels ofthemultiplexers
will overlap momentarily, which may be objection-
able in certain applications. Also when a channel is
turned ON or OFF by an address input, there is a
momentary conductive path from the channel to
VSS, which will drump some charge fromany capa-
citorconnected totheinput or output of the channel.
The inhibit input turning on a channel will similarly
drumpsome charge to V
SS
.
The amountof charge dumped is mostly a function
of the signallevel above V
SS
.
Typically, ay V
DD
- V
SS
= 10V, a 100 pF capacitor
connected to the input or output of the channel will
removed
from
the
lose 3-4% of itsvoltageat the moment the channel
turns ON or OFF.This loss of voltage is essentially
independent of the address or inhibit signal trnasi-
tion time, if the transition time is less than 1- 2
μ
s.
When the inhibit signal turns a channel off, there is
no changedumping of V
SS
. Rather, there is a slight
risein the channel voltage level (65 mVtyp.) due to
the capacitance coupling from inhibit input to chan-
nel input or output. Address input also couplesome
voltagesteps onto the channel signallevels.
In certain applications, the external load-resistor
current may include both V
DD
and signal line com-
ponents.To avoiddrawing V
DD
currentwhen switch
current flows into the transmission gate inputs, the
voltagedrop acrossthebidirectionalswitchmustnot
exceed0.8V (calculated fromR
ON
values shown in
ELECTRICAL CHARACTERISTICS CHART). No
VDDcurrent willflowthrough R
L
iftheswitch current
flows into terminal 1 on the
HCC/HCF4067B
, termi-
nals 1 and 17 on the
HCC/HCF4097B.
HCC/HCF4067B HCC/HCF4097B
11/16