“Industry's first” +3.3V dual SCART saves power and reduces component count in set-top boxes and A/V receivers
(Technology News, 21 Apr 2008 )
Maxim Integrated Products has introduced the MAX9598, said to be the industry's first +3.3V dual SCART solution for set-top boxes and A/V receivers that have two SCART connectors. This device utilizes power-saving, "green" technology to achieve the industry's lowest power consumption. Additionally, the MAX9598 integrates the Company's patented DirectDrive(TM) technology to prevent click-and-pop noise and eliminate the need for costly AC-coupling capacitors on the audio outputs.* Available in a space-saving, 6mm x 6mm TQFN package, the MAX9598 is the industry's smallest complete dual SCART solution.
The MAX9598 is a switch matrix that eases routing of audio and video signals between an MPEG decompression chip and two external SCART connectors. The audio and video channels feature input-source-selection multiplexers, input buffers, and output buffers for routing all inputs to selected outputs. The MAX9598 integrates standard-definition video filters on all video encoder inputs, and all audio drivers deliver a full-scale (2.0Vrms, min) output. The device also integrates input-video-signal and video-load detection circuitry. Controlled through an I2C-compatible interface, the MAX9598 fully complies with the EN50049-1 SCART standard.
Going Green: Traditional Design Challenges
Traditionally, dual SCART devices require +5V and +12V supply voltages. Video signals operate from the +5V supply; audio and slow-switching signals operate from the +12V supply. Traditional solutions can thus consume up to 660mW of operating power.
In the past, power consumption was only a secondary consideration for set-top box and A/V receiver applications. Today, however, under increasing pressure from governmental agencies and consumers to "go green," set-top box manufacturers are looking for ways to drastically reduce the amount of power their boxes consume. Designed to satisfy emerging power-consumption guidelines, the MAX9598 makes it much easier to implement green set-top box applications. Industry's Lowest Power, Dual SCART Solution
While competing dual SCART devices require +5V and +12V supplies, the MAX9598 operates audio and video circuitry from +3.3V and only requires +12V for the slow-switching signal. An internal charge pump inverts the +3.3V supply and generates a -3.3V supply, thereby providing sufficient voltage swing to support 2.0Vrms audio. Combined with the device's low operating current, this low-voltage operation drastically reduces power consumption. Consuming only 70mW of quiescent power, MAX9598 requires 9x less power than a typical 660mW solution.
Additionally, the MAX9598's integrated input-video-signal and video-load detection circuitry allows system designers to intelligently reduce power consumption for their entire system, depending on the situation. The load-detection circuitry can notify the main system controller that a SCART connector has been plugged in or unplugged. If a video load is absent, the system designer may want to put the entire set-top box into a standby mode. Also, if an input video signal is not present, the MAX9598's output amplifiers can be shut down to conserve power.
