Datasheet

ADV3226/ADV3227
Rev. 0 | Page 23 of 24
The basic concept in constructing larger crosspoint arrays is to
connect inputs in parallel in a horizontal direction and to wire-OR
the outputs together in the vertical direction. The meaning of
horizontal and vertical can best be understood by referring to
Figure 65, which illustrates this concept for a 32 × 32 crosspoint
array that uses four ADV3226 or ADV3227 devices.
high output disabled impedance minimizes signal degradation
when paralleling additional outputs.
CREATING LARGER CROSSPOINT ARRAYS
The ADV3226/ADV3227 are high density building blocks for
creating crosspoint arrays of dimensions larger than 16 × 16.
Various features, such as output disable, chip enable, and gain-
of-1 and gain-of-2 options, are useful for creating larger arrays.
When required for customizing a crosspoint array size, they can
be used with the AD8108 and AD8109, which are a pair of
(unity-gain and gain-of-2) 8 × 8 video crosspoint switches, or
with the AD8110 and AD8111, a pair of (unity-gain and gain-
of-2) 16 × 8 video crosspoint switches.
ADV3226
OR
ADV3227
ADV3226
OR
ADV3227
ADV3226
OR
ADV3227
ADV3226
OR
ADV3227
The first consideration in constructing a larger crosspoint is to
determine the minimum number of required devices that are
required. The 16 × 16 architecture of the ADV3226/ADV3227
contains 256 points, which is a factor of 64 greater than a 4 × 1
crosspoint (or multiplexer). The benefits realized in PCB area
used, power consumption, and design effort are readily apparent
when compared to using multiples of these smaller 4 × 1 devices.
To obtain the minimum number of required points for a non-
blocking crosspoint, multiply the number of inputs by the number
of outputs. Nonblocking requires that the programming of a given
input to one or more outputs does not restrict the availability of
that input to be a source for any other outputs. Some nonblocking
crosspoint architectures require more than this minimum. In
addition, there are blocking architectures that can be constructed
with fewer devices than this minimum. These systems have
connectivity available on a statistical basis that is determined
when designing the overall system.
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IN 00–15
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TERM
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IN 16–31
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08653-062
Figure 65. A 32 × 32 Nonblocking Crosspoint Switch Array
Each input is uniquely assigned to each of the 32 inputs of the two
devices and terminated appropriately. The outputs are wired-OR’ed
together in pairs. Enable the output from only one wire-OR’ed
pair at any given time. The device programming software must
be properly written to prevent multiple connected outputs from
being enabled at the same time.
For a complete 32 × 32 array in a single device, refer to the AD8117
and AD8118 for high bandwidth or the ADV3200 and
ADV3201 for lower bandwidth. Also available are 32 × 16 arrays in
a single package: AD8104, AD8105, ADV3202, and ADV3203.