Dual-SCART Video Switch is Ideal for Low-End, European SCART Set-Top Boxes
SUNNYVALE, CA-April 24, 2006-Maxim Integrated Products (NASDAQ: MXIM)
introduces the MAX7457, a 4-channel video switch. The MAX7457 filters
and buffers CVBS, R, G, and B video signals, which makes it ideal for
European Dual-SCART set-top boxes with a VCR loop-through. Today, all
audio and video switching in European STBs utilize a costly
integrated A/V switch offering high-end features, such as volume
control and high audio drive capability. A more cost-effective
solution uses the MAX7457 for the video switching, along with
low-cost standard analog switches for the audio switching. This cost
of this latter approach is 50% less than using integrated A/V
switching devices.
The MAX7457 video switch is used in anti-aliasing and DAC-smoothing
video applications or wherever analog video is reconstructed from a
digital data stream, such as cable/satellite/terrestrial set-top
boxes, DVD players, Hard Disk Recorders (HDR), and personal video
recorders (PVRs). The device uses a continuous-time,
butterworth-type-response lowpass filter to attenuate the sampling
frequency of the DAC encoder. All video signal-timing extraction and
clamping are done within the device, allowing excellent video
performance while saving design time and board space.
The MAX7457 operates from a single +5V supply and has a flat passband
out to 5MHz, ideal for PAL video signals with a stopband of 43dB at
27MHz. The output buffer has a fixed gain of +6dB capable of driving
two standard video loads with a 2Vp-p signal. Output disable control
is also through an external pin. The MAX7457 is available in the
extended (-40° Celsius to +85° Celsius) temperature
range, with prices starting at $1.62 (1000 up, FOB USA).
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