AD9300

–7–

REV. A

Figure 8. Pulse Response

Figure 10. Enable to Channel

“Off” Response

Figure 9. T-Step Response

CROSSPOINT CIRCUIT APPLICATIONS

Four AD9300 multiplexers can be used to implement an 8

× 2

crosspoint, as shown in Figure 11. The circuit is modular in

concept, with each pair of multiplexers (#1 and #2; #3 and #4)

forming an 8

× 1 crosspoint. When the inputs to all four units

are connected as shown, the result is an 8

× 2 crosspoint circuit.

Figure 11. 8 x 2 Signal Crosspoint Using Four AD9300

Multiplexers

The truth table describes the relationships among the digital in-

ber of crosspoint modules that can be connected in parallel is

limited by the drive capabilities of the input signal sources. High

input impedance (3 M

Ω) and low input capacitance (2 pF) of

the AD9300 help minimize this limitation.

8

2 Crosspoint Truth Table

or

or

or

or

00

0

00

1

01

0

01

1

10

0

10

1

11

0

11

1

Adding to the number of inputs applied to each crosspoint

module is simply a matter of adding AD9300 multiplexers in

parallel to the module. Eight devices connected in parallel result

in a 32

× 1 crosspoint, which can be used with input signals hav-

ing 30 MHz bandwidth and 1 V peak-to-peak amplitude. Even

more AD9300 units can be added if input signal amplitude

and/or bandwidth are reduced; if they are not, distortion of the

output signals can result.

When an AD9300 is enabled, its low output impedance causes

the “off” isolation of disabled parallel devices to be greater than

the crosstalk rejection of a single unit.