Opampl layout issues concerning Ptat

[surianova]

hi!

my bias tail current for opamp is from Ptat. It is use pmos curent mirror from Ptat to mirror other circuit. Plan to use interdigit for layout for the transistor of the tail but find out it very far from Ptat block, if 2 transistor very far, Vth mismatch will occur. how to solve it?

 

[qutang]

layout

let the two transistor connect together, let the current as transfer .

 

[horsehill]

layout

yes,you should let the two transistor closer

 

[surianova]

Re: layout

yes,you should let the two transistor closer

but sometimes very hard to close bcoz it connect to all over the block in the chip.

 

[liuyonggen_1]

Re: layout

Using current transfer to replace voltage transfer!
It's very easy!