current consumption for a crystal driver circuit

How low can we get the current consumption for a crystal driver circuit to be? The frequencies of interest are in the range of 10-30kHz.

Thank you in advance.

The crystal frequency is not high. Several microamperes (uA) maybe OK.

Good RTC chips go down to a few 100 nA current consumption - mostly required for the 32 kHz crystal oscillator.

Obviously, very small area transistors are needed to reduce the capacitance of involved switching nodes, standard logic gates
would have a multiple current consumption. Also driving a few pF load considerably increases the supply current.

I have seen papers for circuits well below 100nA - maybe 20nA to 30nA.

Keith