is found in the

Typical Performance Characteristics sec-

tion for Belden 8281, and can be scaled as stated above to

estimate maximum cable lengths and data rates for UTP.

Category 5 UTP has a characteristic impedance of approxi-

mately 100

Ω. The CLC005 in Figure 13 is used to drive the

twisted pair AC-coupled with a series 0.1 µF capacitor and a

50

Ω resistor in each differential output. The CLC012 Adap-

tive Equalizer requires 800 mV

the cable. A voltage divider is necessary to scale the voltage

to the required level at the input of the CLC012. This resistor

network also provides the correct impedance match for

twisted pair.

For Category 5 UTP, the approximate AEC voltage per

length is 3.75 mV/m (see

Block Description ). The CLC005

provides a trim adjust for fine tuning the output signal with

the resistor R. Refer to the CLC005 datasheet for tuning

directions.

DS100145-33

FIGURE 13. Twisted Pair Equalization

DS100145-34

FIGURE 14. Before and After Equalization at 622 Mbps Through 50 Meters of Category 5 UTP

DS100145-35

FIGURE 15. Typical Measurement Setup

13

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