I would say: it all depends on what you need to do.
...
At the end of the day, it really comes down to the output amplifier spec. Have you already idenfitied a suitable part number?
well... kinda. as now i already designed a circuit to get the job done, and as the output stage it has a AD811, but its a bit exotic.
another possible alternative could be LM7171 (3.5€ in single quantity), which is also pin compatible with the AD811.
(the AD8051 is going to be a different op amp, ill search RS later)
about the pwm i really didnt consider it. i agree that its very handy. ill just use a comparator and the triangular wave, and then square it with the help of a not gate (to also met the 50 ohm output impedance)
the sync its not really useful for me, i have a 4 channel scope and no dedicated sync input, the same goes for the isolated output as the instrument will be battery powered.
anyway, attached there is what i came up with. not drawn there is the switch for the -20 gain, i also want to digitally control the offset with a dac and a differential amplifier.
the idea is to have in the first stage a variable gain of 0.5-5, in the second stage a fixed 4 gain and last a 0.1 gain selectable on the output. this way i can have a output swing that vary from 0.2*0.6V =120mVpp to a 20*0.6V = 12Vpp
any thoughts?