CMOS LO Driver stability?

Hi,

I'm designing an imgae reject mixer and need to over come serious loss in the LO path cause by the RC polyphase filter. for size and efficiency in creating a square wave, I wanted to use a cascade of push-pull amplifier (basically scaled inverters...). I saw a lot of designs using this scheme but the inverter without a relatively small feedback resistor is not stable (in terms of K factor), should it be unconditionally stable, should it be DC coupled?

Thank you