CLC012 datasheet(11/18 Pages) NSC

11 / 18 page

Layout and Measurement (Continued)

Troubleshooting with scope probes can affect the equaliza-

tion. For high data rates, use a

low capacitance probe with

less than 2 pF probe capacitance. Evaluation boards and lit-

erature are available for quick prototyping and evaluation of

the CLC012 Adaptive Cable Equalizer. The CLC012 con-

tains CMOS devices and operators should

use grounding

straps when handling the parts.

Figure 9 shows the CLC012’s internal power supply routing.

Bypass V

CC (pin 4) by:

•

Monolithic capacitor of about 0.1 µF placed less than 0.1”

(3mm) from the pin

•

Tantalum capacitor of about 6.8 µF for large current sig-

nal swings placed as close as convenient to the CLC012

To minimize ringing at the CLC012’s inputs, place a 100

Ω re-

sistor in series with the input. This resistor reduces induc-

tance effects.

Several layout techniques can improve high speed perfor-

mance:

•

Keep input, output and AEC traces well separated

•

Use balanced input termination’s

•

Avoid routing traces close to the CLC012’s input trace

•

Maintain common return points for components

•

Use guard traces

The input lines of the CLC012 use a 100

Ω series resistors at

the input pins. This decreases the inductive effects internal

to the part to reduce ringing on fast rise and fall times. Refer

to the evaluation board layout for further suggestions on lay-

out for the CLC012 Adaptive Equalizer.

EQUALIZATION CURVE

The CLC012 Adaptive Cable Equalizer has a maximum

equalization response as shown in

Figure 10. This response

may be obtained by forcing >0.5V differentially at the AEC

pins.

CABLE EMULATION BOXES

Some cable emulation boxes will not mimic cables correctly.

When evaluating the CLC012, it is strongly recommended

that actual cable be used to determine the various perfor-

mance parameters.

Typical Applications

COAXIAL CABLE RECEIVER (Page 1)

The CLC012 equalizer application shown on page 1 will

equalize a variety of coaxial cables up to lengths that attenu-

ate the signal by 40 dB at 200 MHz. The application shows

the proper connection for a single cable driven with a

DS100145-28

FIGURE 8. Typical Measurement Block

DS100145-29

FIGURE 9. Power Package Routing Fixture

DS100145-30

FIGURE 10. Maximum Equalization Response

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