Coax Cable

R

R

-

-

-

-

+

+

+

+

d

1 d

T

;

360 df

I

TIME (10 ns/DIV)

LMH6628QML

www.ti.com

SNOSAQ1B – DECEMBER 2010 – REVISED MAY 2013

Figure 30. Delay Circuit Response to 0.5V Pulse

The circuit gain is +1 and the delay is determined by the following equations.

(1)

where

•

(2)

The LMH6628QML provides a typical delay of 2.8ns at its

−3dB point.

FULL DUPLEX DIGITAL OR ANALOG TRANSMISSION

Simultaneous transmission and reception of analog or digital signals over a single coaxial cable or twisted-pair

line can reduce cabling requirements. The LMH6628's wide bandwidth and high common-mode rejection in a

differential amplifier configuration allows full duplex transmission of video, telephone, control and audio signals.

In the circuit shown in Figure 31, one of the LMH6628's amps is used as a "driver" and the other as a difference

"receiver" amplifier. The output impedance of the "driver" is essentially zero. The two R's are chosen to match

the characteristic impedance of the transmission line. The "driver" op amp gain can be selected for unity or

greater.

Figure 31. Full Duplex Transmit and Receive using the LMH6628

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