A technique and circuitry interfaces a programmable logic integrated circuit compatible with one voltage level to other integrated circuits compatible with a different voltage level. In particular, an on-chip voltage less than the external supply level of the programmable logic integrated circuit is provided to a core portion of a programmable logic integrated circuit by way of a conversion transistor. In an embodiment, the layout (or physical structure) of the conversion transistor is distributed surrounding the core portion. Externally, the programmable logic integrated circuit will interface with an external supply voltage level. The input and output signals to and from the programmable logic integrated circuit will be compatible with the external supply level.