TA0310/0504

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Christophe Prugne

Technical Marketing, Standard Linear Division

1 Introduction

This paper examines the video applications in which high-speed op-amps can be found.

An overview of the main consumer video applications is presented, along with a review of analog video

formats and bandwidth versus resolution.

Finally, we present ST’s current high-speed op-amp portfolio and give technical support for the

implementation of these products in application.

2 Video applications

Currently, there are two types of video applications: broadcast video and graphics video. Broadcast video

is limited to television signal transmissions with specified bandwidth (Television, Set-Top-Box, DVD

player-recorder, Video Camera, etc.). On the other hand, graphics video meets the needs of computers

without bandwidth limitations. This article is mainly concerned with broadcast video applications.

3 Where do we need high-speed op-amps?

An amplifier stage is needed to drive analog video signals to the television via a 75

Ω video line. The

applications concerned are mostly consumer applications such as set top boxes, DVD player-recorders

and video cameras. In these applications, the output capabilities of the amplifier (output current and

distortion versus load) are very important, as it must drive a video line characterized by low impedance

(75

Ω for video lines).

Televisions also require high-speed op-amps. In TVs; the amplifier ensures good impedance matching

between the video line and the input stage in the TV. The amplifier drives the video signal to the input

stage of a chipset, which features high impedance (on the order of several k

Ω) in parallel with a

High Speed Operational Amplifiers

for 75

Ω Video Lines

Revision 2

TA0310

TECHNICAL ARTICLE