VP551CG

The VP531/VP551 converts digital Y, Cr, Cb, data into analog NTSC/PAL composite video and S-video signals The outputs are capable of driving doubly terminated 75 ohm loads with standard video levels.

The VP531/VP551 device accepts data inputs complying with CCIR Recommendation 601 and 656. The data is time multiplexed on an 8 bit bus at 27MHz and is formatted as Cb, Y, Cr, Y (i.e. 4:2:2). The video blanking and sync information from REC 656 is included in the data stream when the VP531 is working in slave mode.

The output pixel rate of VP531/VP551 is 27MHz and the input pixel rate is half this frequency, i.e. 13.5MHz. All necessary synchronisation signals are generated internally when the device is operating in master mode. In slave mode the device will lock to the TRS codes or the HS and VS inputs.The rise and fall times of sync, burst envelope and video blanking are internally controlled to be within composite video specifications.Two 9 bit digital to analog converters (DACs) are used to convert the digital luminance and chrominance data into analog signals. An inverted composite video signal is generated by summing the complementary current outputs of each DAC. An internally generated reference voltage provides the biasing for the DACs.