Answer:
Continuous voltage is spec'd in the datasheet under maximum working voltage which is the highest voltage to which that device can be subjected continuously over decades/years without breaking down. This is 396 Vrms for ADM3260. This can be converted to it's peak voltage DC value using the formula below:
Voltage RMS Value = Voltage Peak Value/sqrt (2).
Voltage Peak Value = Voltage RMS Value * sqrt(2).