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TA0310

Notes on video line driving

Notes concerning the video input stage

Behavior on capacitive load

As explained in Section 3 on page 1, a high speed op-amp can be used for matching the video signal to

the input stage of a TV or set-top-box. The input of a chip-set (typically the input of an analog to digital

converter) is mainly a pure resistor approximately 1k

Ω or 2kΩ in parallel with a capacitor of some of 10pF.

Figure 15: STm5588 (DVD chip). Fs=54MHz for PV outputs. 12MHz LPF to limit the 54MHz

Figure 16: Fs=74.25MHz for HD outputs. 30MHz LPF to limit the 74.25MHz

12MHz

1Vp-p

Amplitude

Frequency

54MHz

(STm5588)

Filtering

Parasitic frequency due

to sampling of the DAC

42MHz

74.25MHz

(STi7710)

Filtering

Parasitic frequency due

to sampling of the DAC

44.25MHz

30MHz

Frequency

1Vp-p

Amplitude