Hi Oleg, The Max 7000S output driver is of CMOS technology. When the VCCIO is supplied with 5V, the output high level is typically 5V and with minimum spec of 2.4V. Kindly please refer to this document in the link below for ensuring you getting voltage level meeting at least 2.5V. http://www.altera.com/literature/an/an107.pdf Could you kindly please verify if the MOSFET driver input is a voltage driven input? When MOSFET device is voltage driven device, the input current does not affect the operation. Thanks.