Datasheet

H
CL
V
IN
C
HOLD
V
OUT
OTA
OPA615
10
11
7
4
2
3
12
100
Ω
100
Ω
SOTA
100
Ω
SOTA
H
CL
V
IN
C
HOLD
V
OUT
OTA
R
1
R
2
R
2
R
1
= V
IN
x
OPA615
3
12
2
4
7
10
11
100
Ω
100
Ω
100
Ω
G + )
R
2
R
1
7.5
BLANKING
BACK PORCH
100 89 70 59 41 30 11 0
W Y CY GRN MAG R BLU BLK
FRONT PORCH
SYNC TIP
BREEZEWAY
COLOR BURST
LUMINANCE + CHROMINANCE
100
80
60
40
20
10
0
−
20
−
40
IRE UNITS
40 IRE
1V
PP
OPA615
www.ti.com ...................................................................................................................................... SBOS299E –FEBRUARY 2004–REVISED SEPTEMBER 2009
DC-RESTORE SYSTEM
Figure 40 and Figure 41 offer two possible
DC-restore systems using the OPA615. Figure 41
implements a DC-restore function as a unity-gain
amplifier. As can be expected from its name, this
DC-restore circuit does not provide any amplification.
In applications where some amplification is needed,
consider using the circuit design shown in Figure 40.
Figure 41. DC Restoration of a Buffer Amplifier
For either of these circuits to operate properly, the
source impedance needs to be low, such as the one
provided by the output of a closed-loop amplifier or
buffer. Consider the video input signal shown in
Figure 42, and the complete DC restoration system
shown in Figure 40. This signal is amplified by the
OTA section of the OPA615 by a gain of:
Figure 40. Complete DC Restoration System
Figure 42. NTSC Horizontal Scan Line
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