Bandgap Current Reference

[kishore2k4]

current reference

Hi,

I am looking for a bandgap current reference circuit (0.5u n-well process) to use it as a current source for biasing circuits. My understanding is that if a reference source is temperature independant it can also be considered process(corners) independent as many process parameters change with temperature?

I came across this circuit Bandgap Current Reference in a google search. I am interesting in exploring other circuits as well. Basically I am looking for a current source/sink (Iref = approx 50uA-100uA) that can be used in my bias circuit for an op-amp.



Thank You,

 

[PaloAlto]

current reference circuits current addition

Just one small correction:

My understanding is that if a reference source is temperature independant it can also be considered process(corners) independent as many process parameters change with temperature?

That is not true.

A reference (current and / or voltage) source can be made temperature independent.

A voltage reference source can be made corners independent.

A current reference source can NOT be made corners independent, unless you use an external resistor to generate the current. Otherwise, as you can see in your doc, it always depends on the resistor value, which is corner dependent.

If you cannot afford an external resistor, then you have to choose the resistor with smallest corner variation and design your circuit taking that variation into account. That would normally be between 10% and 40% approximately.

 

[erikl]

current reference source

Just one small correction:
...
A current reference source can NOT be made corners independent, unless you use an external resistor to generate the current. Otherwise, as you can see in your doc, it always depends on the resistor value, which is corner dependent. ...

Absolutely correct. Just one small addition: Even if you use an (external) temperature-"independent" resistor, there are still the fast/slow process corners (with all their combinations), and additionally the (statistical important) mismatch deviations (which are usually not considered as process corners, but are process dependent).