Hi again Juraj and thanks for your answer,
Do you mean that ENC28J60 is 5V tolerant on Vdd or some pins?
I found this information but I'm new with this module:
VDD, VDDOSC, VDDPLL, VDDRX, VDDTX............................................................................4.0V
RESET, CS, SCK and SI, with respect to VSS(GND) ............................................... -0.6V to 7.0V
CLKOUT, SO, TPIN+/-, TPOUT+/-, with respect to VSS(GND)..................-0.6V to VDD + 0.6V
It looks like MOSI and SCK of ENC28J60 are 5V tolerant but MISO is tolerant only a little above Vdd.
Of course I'll try your EthernetENC library, I've just installed the latest version. What are the improvements or differences against UIPEthernet.h?
Thanks again, best regards