OPA360 Datasheet, PDF (9/24 Pages) Burr-Brown (TI) – 3V Video Amplifier with 6dB Gain and Filter in SC70

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approximately 60mV. This is well within the linear output
voltage range of the OPA360 with a standard 150Ω video
load. Figure 6 shows the function of the level shifter.
OPA360
SB0S294E − DECEMBER 2003 − REVISED SEPTEMBER 2006
Figure 6. Internal Level Shifter, Shifts Input
Signal by Approximately 60mV to Prevent Sync
Tip Clipping
The level shift function is particularly useful when the
output of the OPA360 is DC-coupled to the video load.
However, it is also helpful when sag correction is
employed. The offset helps to shift the video signal closer
to the positive rail, so that with even a small 33µF coupling
capacitor, the output is well outside the saturation limits of
the OPA360. Figure 7 shows the output swing of the
OPA360, operated on 3.0V supplies, with a 22µF sag
correction capacitor and a 33µF output coupling capacitor.
The test signal is a 50Hz signal constructed to generate a
1/2 black, 1/2 white screen. This video pattern is one of the
most difficult patterns to display because it is the worst
case signal regarding signal swing. A worst case signal
such as this is highly unlikely in normal operation. Any
other signal has a lower swing range. Note in Figure 7 that
neither the white nor the black portion of the video signal
is clipped.
Figure 7. Output Swing with 33mF on 3V Supply
OUTPUT SWING TO GND (SYNC PULSE)
Figure 8 shows the true output swing capability of the
OPA360 by taking the tip of the input sync pulse to a
slightly negative voltage. Even when the output sync tip is
at 8mV, the output shows no clipping of the sync pulse.
Figure 8. Input Sync Tip at −30mV (Output Shows
No Sign of Clipping)
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