Problems of Internal MOSFET in Analog ICs

[Saurabh Bangade]

Hi,
I am working on few of the analog ICs such as synchronous rectifier Boost/Buck Converter (DC-DC Controller) (MAX1763). The problem I am facing is that internal MOSFET is not working while for DC-DC converter (External MOSFET) it works fine..
Another application of Current limiting Switch ( TPS203x), there is a significant voltage drop across it And it is one of most important components in our circuit (acting as a sense resistor).
Can anyone help me in this case..

 

[atripathi]

what do you mean by Internal MOSFET not working"?
can you post your schematic pr picture of it?

 

[FvM]

Do you mean to say, the original chips don't keep their specification? Or do you mean, you are trying to model them and don't get the expected result?

 

[Raza]

How you are connecting MAX1703, as driver or you are trying to use the internal (driving only MOSFETS)driving transistors as the main output MOSFETS (though the output current is 1.5 ampere)? As the datasheet specification say TPS203x is a 0.2 ~ 2 ampere capable switch (33mΩ at 5 volts supply) switch. If the drop is excessive it means the switch is bad, try to check with a new piece.
Still your circuit needed for further comments.