clock drivers low current consumption
Charging and discharging a capacitance C at a frequency f is equivalent to having an effective load resistance \$R = \frac{1}{Cf}\$. (This relationship is the basis of switched-capacitor filters.) Using 30&nbsp;pF and 250&nbsp;MHz, this works out to 133.3&nbsp;&Omega; There's no getting around this relationship &mdash; if you need to limit your current to 500&nbsp;&micro;A, then you need to limit the voltage swing to 133.3&nbsp;&Omega; &times; 500&nbsp;&micro;A = 66&nbsp;mVP-P.