what voltage can the HEF4093 work down to

[Simon]

The datasheet keeps specifying parameters at 5, 10 and 15V but will it wok down to 3V ?

[w2aew]

The datasheet shows a plot of input switching thresholds vs. supply voltage, and the curves only extend down to 4.5V VDD.  So, I suspect that it might not work very well below that supply voltage.  YMMV.

[free_electron]

standard 4000 on 3 volt ...tricky.. depends on the manufacturer.
4093 is a quad schmitt nand gate if i remember correctly. 74lvc132 should work.

[SeanB]

The quoted voltage range is 3-18V, but they are piss poor slow at 3V, basically you barely want to do more than 1kHz at most, as they are charging and discharging internal and external nodes at very low currents. In most cases the outputs are then barely able to sink 1mA, let alone source it.