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The difference between RF MOSFET and a switching MOSFET

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cyberblak

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what is a RF transistor

Hi,

That should be an easy one for those of you that are in the RF field... What is precisely the difference between a RF MOSFET and a regular switching MOSFET? I saw that the parameters in the datasheet are quite different...

I need to find a MOSFET with very low rise/fall times, should I look for a RF Mosfet?

Thanks,

cyberblak
 

what is a RF transistor

RF transistor uses special technology such as deep N well to enhance its speed and noise performance. I suggest you can chose RF transistor for fast application. How ever, models of RF transistors are different from normal transistors and their W/L are always fixed to a few set which may not meet your requirements.
 

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    cyberblak

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what is a RF transistor

how much current do you switch?
 

Re: what is a RF transistor

cyberblak said:
W/L?
Click to expand...
yes, the aspect ratio of the device gate width over gate length
 

Re: what is a RF transistor

yes, the aspect ratio of the device gate width over gate length
Click to expand...

Sorry to be so blunt, but what do you mean? The dimensions of the physical package?

Kasai: I don't switch huge currents... Only ~7A pulsed, for very short durations.

Thanks,

cyberblak
 

Re: what is a RF transistor

He is refereing to the device physics, W and L are the channel dimensions
between the gate and the source, if you look at the formulas that govern a fet
you will see W an L, where the current flows
 

Re: what is a RF transistor

The transistors for switching devices, if used in the core area, are usually smaller than the RF transistor. This is because the RF transistors are usually optimized for low noise, therefore the total width area is much larger in order to reduce the gate resistance. In this case the RF transistors usually has an interdigitated, multiple gate layout, while the switching transistor has a single gate. The switching transistor is usually operated close to it's peak Ft, while the RF transistor is operated much lower than peak Ft.
 

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    cyberblak

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Re: what is a RF transistor

cyberblak said:
yes, the aspect ratio of the device gate width over gate length
Click to expand...

Sorry to be so blunt, but what do you mean? The dimensions of the physical package?
Click to expand...
it's such dimension inside the transistor. we won't find it from the outside. it's about the transistor design, if you want to know, more, its detail.
 

what is a RF transistor

mainly according to their ft.
 

what is a RF transistor

a reduced inter electrode capacitance and lead capacitance can make a ordinary transistor to work as a Rf Transistor
 

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