I stumbled across this claim in the datasheet of the TLV3541 opamp:
The TLV354x output stage is capable of driving standard back-terminated 75-Ω video cables, as shown in Figure 23. By back-terminating a transmission line, the device does not exhibit a capacitive load to its driver. A properly back-terminated 75-Ω cable does not appear as capacitance; the device presents a 150-Ω resistive load to the TLV354x output.
This goes against my understanding very distinctly.
My thinking goes like this:
If the cable is electrically short (say, 1m) and open at the far end, then it will appear as a capacitance (~100 pF). The near-end series resistor will contribute favorably to the phase margin by isolating the opamp from the cable capacitance somewhat, but it does not reduce that capacitance to zero. Notably bandwidth at the far end of the cable is compromised (because R+C form a low-pass filter).
(Plus, 75 Ohm might not even be enough for stable operation into 100pF, according to Figure 8 of the same datasheet, which recommends 120 Ohm instead.)
By comparison, a proper far-end termination indeed makes the cable appear purely resistive (regardless of length). Forward termination eats reflections at the near end, and thus, if the far-end termination was perfect, would not be strictly necessary.
Is TI wrong here, or am I?