It is very important to keep the lead lengths to a minimum

and to provide a low impedance current path by using a

ground-plane on the board.

Caution: If R

of LM7121 would be disturbed and it would have to supply

the full amount of load current. This might damage the part if

power dissipation limit is exceeded.

Color Video on Twisted Pairs Using Single Supply

The circuit shown in

Figure 4 can be used to drive in excess

of 25 meters length of twisted pair cable with no loss of reso-

lution or picture definition when driving a NTSC monitor at

the load end.

DS012348-93

FIGURE 3. Waveform across a 100

Ω Load

www.national.com

15