Maxim Integrated Products' MAX7454/MAX7455 are 3-channel, switchable high-definition/standard-definition (HD/SD)video-reconstruction filters and buffers that are ideal for 1080i, 720p, 480p, and 480i video scanning system standards. Each channel of the MAX7454/MAX7455* combines a lowpass filter with a video buffer capable of driving a standard 150-Ohm video load with a 2 V peak-to-peak signal. The magnitude response of the lowpass filter can be switched between a 10 MHz and 30 MHz bandwidth through a control pin, which allows optimal filtering for HD, SDi, or SDp encoder digital-to-analog (DAC) outputs. The input and output signals are DC-coupled to the MAX7454/MAX7455, eliminating AC-coupling capacitors that consume board space and add cost. These devices are suitable for anti-aliasing or DAC-output video-reconstruction applications in digital video devices such as HD STBss, as well as HDTVs as CRTs, LCDs, plasmas, and DLPs.

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The MAX7454 has an output buffer gain of +6 dB, and the MAX7455 has an output buffer gain of +12 dB. The 3-channel devices are suitable for RGB or Y Pr Pb component video signals in interlaced, progressive scan, or high-definition formats. In HD mode (fc = 30 MHz), each filter channel achieves -55 dB of attenuation at 74.25 MHz, with -2.3 dB of attenuation at 30 MHz. In SD mode (fc = 10 MHz), each filter channel achieves -62 dB of attenuation at 27 MHz, with -0.40 dB of attenuation at 10 MHz. A fine-adjustment control pin is available to optimize the corner frequency of the filter response by 15%.

The MAX7454/MAX7455 save significant board space and design time, while providing increased performance at a cost comparable to the discrete high-definition L-R-C filter and buffer solutions typically used today. The MAX7454/MAX7455 are offered in a 20-TSSOP package and operate over the upper commercial temperature range (-0°C to +85°C). Prices start at $2.75 in quantities of 1000 and up.