I need to supply an external oscillator in 1.8V.
I supply my CY8C4124PVI-442 with 5V.
Can I use Vccd (pin 26) to supply my oscillator ?
The Vccd pin is for decoupling the internal voltage regulator. Its not supposed to power external components. If your oscillator is low-power, it might work. But doing so might introduce unwanted noise and glitches into the internal power rail.
Consider doing this as a solution. You have to
observe max ratings for the Opamp ot, eg. that
it will supply enough I to handle your external osc.
Set up Idac current and select the R to generate the
Forgot to paste schematic -