help with electronic question

[longpole001]

Hi guys ,

would like to confirm with those more knowledgeable on the electronics side of life a problem i am having with looking for an equivalent mosfet for a repair

The componet is a VN0106N5 which has a signal on the gate of 13.5mhz and is faulty ,

Looking at the possible replacement for VN0106N5 and the IRF510-512 series came up in searches

given the input to gate of 13.5mhz gives a 74ns cycle , half a cycle is 37ns

rise half cycle is = turn on delay time + rise time
fall half cycle is turn off delay + fall time


thus spec for IRF510 -513 series says
max rise turn on delay =20ns
max rise time =25ns ,
same for for fall times

so half cycle rise time is max 45ns , fall half cycle is 45ns , i need a max of 37ns at a freq at 13.5mhz

thus this equivilant mosfet wont fit this application

am i correct in my calculations ??


cheers

[Gusse]

Sine waves have predictable shape and timing so rise/fall time (10-90%) can be calculated fairly easy.

RiseTime = (arcsin(0.8))/(PII*Freq) = ~0.2952/Freq -> ~0.3*Period
RiseTime = 74ns * 0.3 = ~22ns

Your FET rise/fall time need to be faster that 22ns.

[Ramius]

If you do a google search the device is manufactured by Supertex which has tech support: http://www.supertex.com/contact_app_engineer.html . There are also several sites that show equivelent devices as well as this site which shows who has a supply of the devices: http://www.ic2ic.com/search.jsp?sSearchWord=VN0106N5&prefix=V .

Best, Ed

[longpole001]

thanks guys , will follow up on links and will apply math calcs

cheers