help needed.-MOSFET as switch

[manju_bhat]

Hi I am using dual N channel and P channel Mosfet for one of my switching application. The part number is IRF7317PBF. The Mosfet is a SO-8 Package.
The pchannel mosfet works fine. But problem is with n channel . Input to the N channel is 5v . and the Gate drive for n channel is 4.5v. So N chnnel should be ON. but somehow N channel out put shows only 4v instaed of 5v. I ahve not connected any load and Rds (ON) is very less, the drop should be in millivolts. I have attched the circuit here. please help. what could be the problem with IRF ? I changed the MOSFET and checked. Still no use. please help

 

[btbass]

I think you need to take the source of the N channel, pin 1 to ground for it to work.
I would also increase the value or R60 and R67 to 4k7.

 

[fmercury]

Did you solve the problem? Where did you get those schematics?

The thing is easy: the MOSFETs are connected via source, instead of drains. This leads to an inconvenience: the internal diodes are forward biased, so you have no control over the output.

Your schematics suggest there's a 5V supply and a 1V signal connected between drains (that should be sources). Therefore, your 4V output.