CH32V307V-EVT-R1 - DAC for scart signal

[blallo]

Hello everyone!
I'm trying to output RGBs from the CH32V307V-EVT-R1 board.

I'm using a r-2r ladder to output RGB888 (R: 270ohm, R2: 560ohm) and it looks decent on the oscilloscope.

The problem is sync: without the scart load, the signal looks perfect (even has frequency of 15.6khz), i put a 330ohm resistor in series since the signal is 3.3vpp, but when i attach it to the scart it gets very noisy (and sync doesn't hold).

Do you have any hints? Thanks!

[fchk]

Try an OpAmp as buffer. Video signals are usually terminated with 75 Ohm, and the source needs to deliver the current.

[blallo]

Do you have any suggestion for a good suited opamp for the purpose?

[HwAoRrDk]

Texas Instruments THS7316 is pretty popular for buffering RGB video.