TGP2108-SM control pins

[nikhil_56]

HI

Iam using TGP2108-SM for digital phase shifter, i have a query regarding the capacitor value that is kept in shunt at the control pins. can anyone suggest value of the capacitors.

 

[KlausST]

Hi,

link to datasheet?
Does the manufacturer provide additional documents, like "application notes"?

Klaus

 

[nikhil_56]

Hi,

link to datasheet?
Does the manufacturer provide additional documents, like "application notes"?

Klaus

https://www.mouser.in/datasheet/2/412/TGP2108_SM_Data_Sheet-1504714.pdf

datasheet for the above component

 

[FvM]

Does the evaluation board use bypass capacitors at control inputs? Image in datasheet suggests it doesn't. GaAs RF switches are typically involving inbuilt series resistance at control inputs acting as low pass. Small capacitors (100 pF range) can help to completely block RF entering or leaving control inputs but are probably not necessary.

 

[nikhil_56]

Does the evaluation board use bypass capacitors at control inputs? Image in datasheet suggests it doesn't. GaAs RF switches are typically involving inbuilt series resistance at control inputs acting as low pass. Small capacitors (100 pF range) can help to completely block RF entering or leaving control inputs but are probably not necessary.

Is it ok to use 0.1uF capacitor in shunt for the control inputs for the TGP2108_SM.

 

[KlausST]

can anyone suggest value of the capacitors.

the datasheet does not show any capacitors.

Where does this idea about the capacitors come from?

Klaus

 

[nikhil_56]

the datasheet does not show any capacitors.

Where does this idea about the capacitors come from?

Klaus

In another phase shifter they recommended to use capacitor at control inputs

 

[KlausST]

In another phase shifter they recommended

in another phase shifter?

Isn´t it like:
I want to bake a chocolate cake.
But in another cake receipe they used pineapple.

Why should I care about the other cake receipe?
Or did I misunderstand something?

Klaus

 

[FvM]

Intended switching speed gives an upper limit for control signal bypass capacitors.

--- Updated May 8, 2024 ---

the datasheet does not show any capacitors.

Right, and I gave an explanation why they are probably not necessary. But explicitly mentioned in datasheet or not, there's nothing against thinking on your own.

 

[KlausST]

there's nothing against thinking on your own.

Very true.

What I wonder is: .. If I personally have an idea about modifying a circuit .... it´s my idea. So it´s me, who should have a reason for this modification. I do this because I want to achieve a goal. And I should have a description or in best case a value for this goal.

But I completely miss this here. I don´t know what the OP wants to achieve, I miss a goal.
And this is what I don´t undersand. The OP asks us for a capacitor value. The question seems so random.

We probably could answer the question if we had a goal.

Klaus