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STV9212

Functional Description

signal top limitation.

2.8.1

Output Clamp

The DC position of video infra-black and video black levels at the video outputs must be fixed

regardless of video or OSD inset contents, especially in applications where the device’s output

infra-black level determines directly the infra-black level on the CRT cathodes (DC-coupled

applications). This fixing is achieved by means of a fully-integrated output clamp that brings the

output video infra-black level (video black level, in absence of the BLK pulse) to the level of a

pulse must entirely fall into the VIP pulse if this is present (clamp of infra-black level) or onto the

video black part (clamp of black level). In the former case, the OCP generator is to be triggered with

OCP timings, triggered by the BLK trailing edge, are not shown as they have no practical use.

2.8.2

Bandwidth Control

Controlled via bits

BW[3:0], the output stage can limit the rise and fall time of the output signal. The

2.8.3

Output Buffer

The output buffer provides enough current so that external buffers are not required and the power

amplifier can interface directly to the device’s outputs.

Figure 13: Output Stage

BLKI

output stage

Video before

Output

Note: Identical for video channels 2 and 3.

OCP

OUT1

OCP

22

GND

VCCP

15

+

-

Infra-black Level

Clamp & Buffer