Fastest signal that can be read off-chip?

[tasctasc]

I have an analog signal that is generated on-chip and is periodically reset to a known a known value (1V) resulting in a somewhat digital signal. In other words, the output signal goes from 1V to a low value (not zero) and then is reset to 1V and then drops to a different low value, reset to 1V again, etc. I know that it is difficult to accurately obtain high frequency signals off-chip since the parasitics of the packaging distorts the signals. Is someone able to tell me what the fastest frequency I can run the circuit at so that the low (analog) signal value of the output signal can be accurately sent off-chip.
Thanks in advance.

 

[adix]

It depends on noise, power consumption, heating..Typical output capacitance is around 10pF. Use class AB buffer and you get something like hundreds of MHz speed.