FMS6404 Datasheet, PDF (1/9 Pages) Fairchild Semiconductor – Precision Composite Video Output with Sound Trap and Group Delay Compensation

October 2011
FMS6404
Precision Composite Video Output with Sound Trap and
Group Delay Compensation
Features
 7.6MHz 5th-Order Composite Video Filter
 14dB Notch at 4.425MHz to 4.6MHz for Sound Trap
Capable of Handling Stereo
 50dB Stopband Attenuation at 27MHz on
CV Output
 > 0.5dB Flatness to 4.2MHz on CV Output
 Equalizer and Notch Filter for Driving RF Modulator
with Group Delay of -180ns
 No External Frequency Selection Components
or Clocks
 < 5ns Group Delay on CV Output
 AC-Coupled Input
 AC- or DC-Coupled Output
 Capable of PAL Frequency for CV
 Continuous Time Low-Pass Filters
 <1.4% Differential Gain with 0.7° Differential Phase
on CV Channel
 Integrated DC Restore Circuitry with Low Tilt
Applications
 Cable Set-Top Boxes
 Satellite Set-Top Boxes
 DVD Players
Description
The FMS6404 is a single composite video 5th-order
Butterworth low-pass video filter optimized for minimum
overshoot and flat group delay. The device contains an
audio trap that removes video information in a spectral
location of the subsequent RF audio carrier. The group
delay compensation circuit pre-distorts the signal to
compensate for the inherent receiver intermediate
frequency (IF) filter’s group delay distortion.
In a typical application, the composite video from the
DAC is AC coupled into the filter. The CV input has DC-
restore circuitry to clamp the DC input levels during
video synchronization. The clamp pulse is derived from
the CV channel.
All outputs are capable of driving 2V_PP, AC- or DC-
coupled, into either a single or dual video load. A single
video load consists of a series 75Ω impedance
matching resistor connected to a terminated 75Ω line.
This presents a total of 150Ω of loading to the part. A
dual load would be two of these in parallel, which
presents a total of 75Ω to the part. The gain of the CV
signal is 6dB with 1V_PP input levels. All video channels
are clamped during synchronization to establish the
appropriate output voltage reference levels.
Related Resources
 AN-6024 – FMS6xxx Product Series Understanding
Analog Video Signal Clamps, Bias, DC Restore,
and AC or DC coupling Methods
 AN-6041 – PCB Layout Considerations for Video
Filter / Drivers
Ordering Information
Part Number
Operating
Temperature Range
FMS6404CSX
-40°C to +70°C
Package
Packing Method
8-Lead, Small-Outline Integrated Circuit (SOIC),
JEDEC MS-012, .150" Narrow Body
2500 Units
per Reel
© 2011 Fairchild Semiconductor Corporation
FMS6404 • Rev. 1.0.0
www.fairchildsemi.com