AD8114AST Analog Devices Inc, AD8114AST Datasheet - Page 21

• Manufacturer Part Number: AD8114AST
• Description: IC VIDEO CROSSPOINT SWIT 100LQFP
• Manufacturer: Analog Devices Inc

Specifications of AD8114AST

• Rohs Status: RoHS non-compliant
• Function: Video Crosspoint Switch
• Circuit: 1 x 16:16
• Voltage Supply Source: Dual Supply
• Voltage - Supply, Single/dual (±): ±4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 100-LQFP
• Array Configuration: 16x16
• Number Of Arrays: 1
• Screening Level: Industrial
• Pin Count: 100
• Package Type: LQFP
• Power Supply Requirement: Dual
• Lead Free Status / RoHS Status: Not Compliant

Using additional crosspoint devices in the design can lower the
number of outputs that must be wire-OR’ e d together. Figure 49
shows a block diagram of a system using eight AD8114s and
two AD8115s to create a nonblocking, gain-of-2, 128 × 16
crosspoint that restricts the wire-OR’ing at the output to only
four outputs.
Additionally, by using the lower eight outputs from each of the
two Rank 2 AD8115s, a blocking 128 × 32 crosspoint array can
be realized. There are, however, some drawbacks to this
technique. The offset voltages of the various cascaded devices
will accumulate, and the bandwidth limitations of the devices
will compound. In addition, the extra devices will consume
more current and take up more board space. Once again, the
overall system design specifications will determine how to make
the various tradeoffs.
MULTICHANNEL VIDEO
The excellent video specifications of the AD8114/AD8115 make
them ideal candidates for creating composite video crosspoint
switches. These can be made quite dense by taking advantage of
the AD8114/AD8115’s high level of integration and the fact that
IN 96–111
IN 00–15
IN 48–63
IN 64–79
IN 80–95
IN 112–127
IN 16–31
IN 32–47
16
16
16
16
16
16
16
16
R
R
R
R
R
R
R
R
TERM
TERM
TERM
TERM
TERM
TERM
TERM
TERM
(8 × AD8114)
Figure 49. Nonblocking 128 × 16 Array (128 × 32 Blocking)
AD8114
AD8114
AD8114
AD8114
AD8114
AD8114
AD8114
AD8114
RANK 1
128:32
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
Rev. B | Page 21 of 32
8
1k Ω
8
1kΩ
8
1kΩ
8
1kΩ
32:16 NONBLOCKING
composite video requires only one crosspoint channel per
system video channel. There are, however, other video formats
that can be routed with the AD8114/AD8115 requiring more
than one crosspoint channel per video channel.
Some systems use twisted-pair wiring to carry video signals.
These systems utilize differential signals and can lower costs
because they use lower cost cables, connectors and termination
methods. They also have the ability to lower crosstalk and reject
common-mode signals, which can be important for equipment
that operates in noisy environments or where common-mode
voltages are present between transmitting and receiving
equipment.
In such systems, the video signals are differential; there is a
positive and negative (or inverted) version of the signals. These
complementary signals are transmitted onto each of the two
wires of the twisted pair, yielding a first-order zero common-
mode voltage. At the receive end, the signals are differentially
received and converted back into a single-ended signal.
When switching these differential signals, two channels are
required in the switching element to handle the two differential
(32:32 BLOCKING)
AD8115
AD8115
RANK 2
8
8
8
8
OUT 00Ð15
NONBLOCKING
ADDITIONAL
16 OUTPUTS
(SUBJECT
TO BLOCKING)
AD8114/AD8115