CLC012 datasheet(12/18 Pages) NSC

12 / 18 page

Typical Applications (Continued)

CLC005 driver. Loss of Signal (LOS) is connected to MUTE

to latch outputs DO and DO in the absence of an input signal

to the equalizer.

Refer to the CLC012’s evaluation board layout for additional

suggestions.

National can supply most of the major components required

to design a transmission line repeater.

Figure 11 shows a

typical repeater design using the CLC005, CLC012, and the

CLC016. The design functions supported by each chip are:

CLC005: Cable connection chip

Boosts drive for transmission to next repeater or

final destinations

CLC012: Receive serialized digital data from incoming

transmission lines

Equalizes the incoming data

CLC016: Retimes the equalized data (improving jitter)

The CLC016 is a multi-rate data retiming PLL. The circuit

(

Figure 11) will work at up to 4 different data rates with no ad-

ditional components or manual tuning.

DIGITAL VIDEO (SDV) ROUTERS

The CLC012 provides performance that complies with the

ITU-T G.703 standard for serial digital data transmission

over coaxial cable. One common application is in routers,

which provide a switching matrix for connecting source

equipment to destination equipment.

Figure 12 shows a typical configuration for a router, including

equalizers, a crosspoint switch, data retimers, and cable

drivers. The CLC012 is used in its standard configuration in

this application, and automatically equalizes cable lengths

from zero meters to greater than 300 meters at 360 MHz

(see plots in

Typical Performance Characteristics sec-

tion). The equalized outputs are connected to the differential

inputs of the crosspoint switch. The CLC016 Data Retimer

receives the data from the crosspoint and performs the clock

and data recovery functions, further reducing jitter. Finally,

the retimed data is driven into the coaxial cable by a CLC005

ITU-T G.703 Cable Driver (with two amplitude-adjustable

outputs).

TWISTED PAIR DRIVER

A low-cost medium for transmitting data is twisted pair. Cat-

egory 5 UTP has an attenuation characteristic similar to

Belden 8281 coaxial cable but scaled in length: 120 meters

of Category 5 UTP is roughly equivalent to 300 meters of

Belden 8281 cable. When properly implemented, the

CLC012 will equalize data rates up to 625 Mbps over Cat-

egory 5 UTP. The maximum data rate depends upon the

cable length. A plot of Maximum Data Rate vs Cable Length

DS100145-31

FIGURE 11. Typical Repeater Design

DS100145-32

FIGURE 12. Data Routing Block Diagram

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