CD22101 and CD22102 crosspoint switches consist of
4 x 4 x 2 arrays of crosspoints (transmission gates) with a
4-line to 16-line decoder and 16 latch circuits. Any one of
the sixteen crosspoint pairs can be selected by applying
the appropriate four-line address, corresponding
crosspoints in each array are turned on and off
simultaneously. Any number of crosspoints can be turned
on simultaneously.
In the CD22101, the selected crosspoint pair can be
turned on or off by applying a logic ONE or ZERO,
respectively, to the data input, and applying a ONE to the
strobe input. When the device is “powered up”, the states
of the 16 switches are indeterminate. Therefore, all
switches must be turned off by putting the strobe high,
data-in low, and then addressing all switches in
succession.
The selected pair of crosspoints in the CD22102 is turned
on by applying a logic ONE to the KA (set) input while a
logic ZERO is on the KB input, and turned off by applying
a logic ONE to the KB (reset) input while a logic ZERO is
on the KA input. In this respect, the control latches of the
CD22102 are similar to SET/RESET flip-flops. They differ,
however, in that the simultaneous application of ONEs to
the KA and KB inputs turns off (resets) all crosspoints. All
crosspoints in both devices must be turned off as VDD is
applied.