EL2030C
120 MHz Current Feedback Amplifier
can be optimized when the supplies are increased
g
tions. This is primarily due to a reduction in in-
ternal parasitic junction capacitance with in-
creased power supply voltage.
Video Applications Ð Contd.
to 15V, especially at 30 MHz HDTV applica-
Video signals are 1V peak-peak in amplitude,
from sync tip to peak white. There are 100 IRE
(0.714V) of picture (from black to peak white of
the transmitted signal) and 40 IRE (0.286V) of
e
sync in a composite video signal (140 IRE
1V).
The following table summarizes the behavior of
g
g
the EL2030 at 5V and 15V for NTSC. In ad-
dition, 30 MHz HDTV data is included. Refer to
the differential gain and phase typical perform-
ance curves for more data.
For video applications where a gain of two is
used (double termination), the output of the vid-
eo amplifier will be a maximum of 2V peak-peak.
g
With
5V power supply, the EL2030 output
swing of 3.5V is sufficient to satisfy the video
output swing requirements. The EL2030 can
drive two double terminated coax cables under
g
V
s
Rload A DGain DPhase
Comments
v
15V
75X
1
1
1
2
2
2
2
0.02%
0.02%
0.05%
0.02%
0.01%
0.03%
0.05%
0.03
0.02
0.02
0.08
0.02
0.09
0.02
Single terminated
§
§
§
§
§
§
§
15V 150X
5V 150X
Double terminated
Double terminated
Single terminated
g
four double terminated cables is feasible.
these conditions. With
15V supplies, driving
15V
75X
15V 150X
5V 150X
15V 150X
Double terminated
Double terminated
HDTV, Double terminated
Although the EL2030’s video characteristics (dif-
ferential gain and phase) are impressive with
g
5V supplies at NTSC and PAL frequencies, it
Equivalent Circuit
2030–18
11
ELANTEC [ ELANTEC SEMICONDUCTOR ]
