Problem with BF_960 Transistor

Hello Friends.I have to make receicer with BF 960 transistor.When I making footprint for transistor,i made a mistake.
Can you tell me are two gate's are interchangeable?
Betsregards:Barosov
edit: removed mai address

derser said:

Hello Friends.I have to make receicer with BF 960 transistor.
When I making footprint for transistor,i made a mistake.
Can you tell me are two gate's are interchangeable?

Click to expand...

No, you can not.

derser said:

Hello Friends.I have to make receicer with BF 960 transistor.When I making footprint for transistor,i made a mistake.
Can you tell me are two gate's are interchangeable?
Betsregards:Barosov
edit: removed mai address

Click to expand...

If the MOS transistor has a symmetric structure, you can interchange the Gates.Get technical support from the manufacturer..( they know better than us)

BigBoss said:

If the MOS transistor has a symmetric structure, you can interchange the Gates.Get technical support from the manufacturer..( they know better than us)

Click to expand...

Wrong.
You can not interchange drain and source, since protection diodes are connected to gates.

Imagine a dual gate transistor as a cascode of two single gate transistors. Obviously the gates have different effect in a circuit and can't be exchanged. There's a reason why G1 pin is located next to source and G2 next to drain.

A symmetrical transistor allows to interchange both gates together with source and drain. But BF960 isn't symmetrical (source tied to substrate, protection diodes as already mentioned). And it won't solve your problem of crossed G1/G2 anyway.

FvM said:

Imagine a dual gate transistor as a cascode of two single gate transistors. Obviously the gates have different effect in a circuit and can't be exchanged. There's a reason why G1 pin is located next to source and G2 next to drain.

A symmetrical transistor allows to interchange both gates together with source and drain. But BF960 isn't symmetrical (source tied to substrate, protection diodes as already mentioned). And it won't solve your problem of crossed G1/G2 anyway.

Click to expand...

Dear FvM,

I have illustrated a full symmetrical MOS which I tried to explain and these types of MOS transistors are frequently used in RFIC circuits.
I meant IF the structure of BF960 is as follows, the gates are interchangeable otherwise of course not..
View attachment BF960_illustration.png

BigBoss said:

I meant IF the structure of BF960 is as follows, the gates are interchangeable otherwise of course not..

Click to expand...

Your structure is a parallel structure of two FETs with common drain.

BF960 is a cascode connection.

Going to the original question:

"Can you tell me are two gate's are interchangeable?"
The answer is: Depends by your application.

Originally the Dual-Gate MOSFET was invented to get a gain-controlled device (input signal on G1, and DC gain-control on G2). Also this device can be used as an RF mixer, applying two RF signals to the gates, and output to the drain.

Generally the Gate1 of the device has narrower gate than Gate2, so has lower capacitance than Gate2.
The DC bias applied on G1 it will have less influence on the transistor drain current, than if is applied on G2.

So, if you use the device to mix two RF signals, the device might work if you interchange the gates.
But if the device is used as controlled-gain amplifier (input signal on G1, and DC gain-control on G2) you cannot interchange the gates.