Temperature Coefficient Inductance

[mattiad]

Hi Everybody,

I'm studying the behavior in temperature of many components in integrated circuits.
Can anyone tell me something about inductance and varactor? How they change in temperature? Do the increase or decrease?

Mattia

 

[erikl]

Like any other component: Depends on their

• material & substrate
• geometry
• parasitics

 

[mattiad]

Thank you for the information, do you know if generally inductors increase with temperature?

 

[erikl]

Thank you for the information, do you know if generally inductors increase with temperature?

Don't know. Standard inductors' model files just contain the temperature dependency of their parasitics (resistors & capacitors). Hence I suppose the temp. dep. of the inductor itself is negligible. Temperature-caused extension of the inductor's material doesn't give an explicit trend - that depends on its geometry. For spiral inductors I'd assume a small positive temp. dep. due to the increase of mutual coupling between its windings. Again depends on its geometry (winding distance).

 

[love_analog]

I have studies this on silicon.
Inductance doesn't change much with temp. Its the resistance of the metal. So the Q does change, also by a small amount. This Q changes cause a change in the frequency of an LC oscillator by a small amount.