LMH6683 Datasheet, PDF (17/30 Pages) Texas Instruments – 190MHz Single Supply, Dual and Triple Operational Amplifiers

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LMH6682, LMH6683
SNOSA43A – MAY 2004 – REVISED APRIL 2013
Figure 52.
This property of the LMH6682/83 guaranties a higher slew rate at higher differential input voltages.
ΔV/Δt = ΔV*Gm/C
(5)
In Figure 53 one can see that a higher transient voltage than will lead to a higher slew rate.
Figure 53.
HANDLING VIDEO SIGNALS
When handling video signals, two aspects are very important especially when cascading amplifiers in a NTSC- or
PAL video system. A composite video signal consists of both amplitude and phase information. The amplitude
represents saturation while phase determines color (color burst is 3.59MHz for NTSC and 4.58MHz for PAL
systems). In this case it is not only important to have an accurate amplification of the amplitude but also it is
important not to add a varying phase shift to the video signals. It is a known phenomena that at different dc
levels over a certain load the phase of the amplified signal will vary a little bit. In a video chain many amplifiers
will be cascaded and all errors will be added together. For this reason, it is necessary to have strict requirements
for the variation in gain and phase in conjunction to different dc levels. As can be seen in the tables the number
for the differential gain for the LMH6682/83 is only 0.01% and for the differential phase it is only 0.08° at a supply
voltage of ±5V. Note that the phase is very dependent of the load resistance, mainly because of the dc current
delivered by the parts output stage into the load. For more information about differential gain and phase and how
to measure it see Application Note OA-24 SNOA370 which can be found on via TI's home page
http://www.ti.com
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Product Folder Links: LMH6682 LMH6683
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