Video function

Dual integrated video low-pass reconstruction filter output

Integrated output driver provides low impedance output

Transfer 2Vp-p (6dB gain) composite video into 150 Ω.

7.1MHz Fourth-Order Video Filter

0.4% differential gain, 0.4° differential phase

Integrated DC Restoration/Clamping Circuit

application

CCTV

Cable and satellite set-top boxes

DVD player

television

HDTV

Personal Video Recorder (PVR)

Video on Demand (VOD)

General Instructions

The FMS6414 dual-channel video filter driver chip provides comprehensive video filtering applications for set-top boxes or DVDs. This section consists of two fourth-order video pass video filters. This device integrates video so that it can be driven directly to the outside world. The video signal is filtered and buffered at 7.1 MHz to drive 2Vp-p into an AC-coupled 150Ω load with a maximum load capacitance of 35pF at the output. The optimization of the filter approximating the fourth-order Butterworth characteristic is towards low overshoot and flat group delay. Likewise, they are able to drive a 75Ω load at 1Vp-p. There is a DC coupled option for the video output driven to 1 output.

Functional block diagram

Introduction to function description

The FMS6414 is a monolithic continuous-time video filter designed to reconstruct luminance, chrominance, or composite video signals from D/A sources. chip is used for AC-coupled input and

AC coupled output. (See Fig.) Reconstruction Filter Optimization of a 4th-order Butterworth Approximate Flat Group Delay with Low Overshoot. Each video output is capable of driving 2VP-P into an AC-coupled 150Ω video load with up to 35pF of capacitance at the output pin. The channels are synchronizing to establish the proper output voltage swing range. Therefore, the behavior of the input coupling capacitor does not conform to the conventional RC time constant. All clamped channels sink below 10 mV of the video input source within 5 ms. In most applications, the input coupling capacitor is 0.1µF. The input is usually on active video, nominally tilting the horizontal line about 2mV for the video output. During synchronization, the clamp typically sources 20 microamps to restore the DC level. The end result is zero average input current. Any change in the value of the coupling capacitor in the input will reverse the slope of each row.

This change also affects the gripper response time linearly. This product is robust and stable under all conditions of specified load and input conditions. Capacitor bypassing VCC directly to ground ensures this performance. Video Input/Output The video input is driven by a low impedance 1VP-P supply or the output of a 75Ω terminated line. The input needs to be AC coupled through a 0.1µF capacitor, allowing 5ms of settling time. The video output is capable of driving an AC-coupled 150Ω load with 2VP-P or 1VP-P into a 75Ω load. Load capacitance up to 35pF (at the output pin) can drive under unstable conditions or solve problems. The output is an AC-coupled 220µF or larger AC-coupling capacitor.

Typical application diagram

Absolute Maximum Ratings (exceeding the device may be damaged)

NOTE: None of the functional operation under these conditions is implied. Performance and reliability are guaranteed not to exceed operating conditions only under the following conditions.

operating conditions

Electrical Characteristics

1Vp-p signal at room temperature

notes:

1. The peaking capacitor adds nominally 0.7dB to the 4.2MHz output

2. Continuous short circuit protection limited to 10 seconds