Offset drift in Reference.

[fredflinstone]

Hi,

I am trying to simulate offset drift of voltage reference output in SPICE. But not sure whether I am doing it right. I think simulating the low frequency flicker noise of the buffer input pair is the way to simulate offset drift.. Am I right here? Is there any other factors which affects the offset drift?

Thanks in advance

fred

 

[FvM]

Offset and offset drift are usually regarded as DC parameters, while noise is an AC parameter. So they are basically different and not related anyway. Offset drift would be analyzed by applying temperature variation in DC analysis.

Practically, I see a relation of offset drift and low frequency noise in so far, as the low frequency noise observed in a real circuit is partly caused by thermal fluctuations, e. g. due to the components exposed to forced and convective air flow. Noise from these effects has to be added to low frequency noise specification, but it's generally not considered in simulation models. The effect is strong with components that have a considerable thermal drift as amplifiers with individual transistors. It may also play a role in low frequency noise of voltage references.

 

[fredflinstone]

Hi FvM,

Thanks a lot...

I was trying to simulate the drift in offset with time. So I thought if i find out the low frequency part of flicker noise which basically gives degradation of transistors with time.

if i am right you are suggesting to do temp sweep and find offset. But this will give me drift across temp not offset drift with time