来源：芯片解密-龙芯世纪 时间：2011-04-07 阅读：872次
The MAX4455 is an eight-channel arbitrary graphics on-screen display (OSD) video generator that inserts arbitrary gray-scale bit-mapped graphics into eight asynchronous composite video sources. Ideal for security camera surveillance systems, the MAX4455 supports the insertion of graphics and text on up to eight video output channels in 15 levels of brightness. It easily displays information such as company logo, camera location, time, and date with arbitrary fonts and sizes. Arbitrary graphics capability enables the display of unique languages and fonts, allowing manufacturers to tailor their system for any geographic market. The MAX4455 is designed to work with Maxim's video crosspoint switches, such as the MAX4356 and MAX4358, which include circuitry that simplifies the insertion of the OSD information. The MAX4455 can also be used with discrete fast mux switches.
The MAX4455 operates from a 3V to 3.6V digital supply, and a 2.7V to 5.5V analog supply. Independent interface supplies enable the MAX4455 to communicate with microprocessors and OSD crosspoint switch logic with logic levels ranging from 2.7V to 5.5V. The MAX4455 uses an external 16Mb SDRAM for graphical image storage for all eight video channels. The MAX4455 manages all memory interface functions, allowing a simple host ?P interface. The MAX4455's multiple-channel memory sharing and multiple-location write function allow fast memory updates of shared graphics information necessary for rapidly changing OSD information, such as a time stamp.
The MAX4455 is available in a thin 100-pin TQFP package (200mm2 area), and is fully specified over the extended temperature range (-40°C to +85°C). The MAX4455EVSYS is available to evaluate the MAX4455 along with the MAX4358 (32 x 16 video crosspoint switch with OSD).