OpAmp Design for CMOS Tempreture Detector

[amic]

Hi all. here is a problem I am working on.

I have two voltages. Vbgr and Vptat which I need to substract Op amp. Vbgr is constant ( around 1.2V ) while Vptat varies from 0.4 V to 0.7V( PTAT voltage). I need to select architecture/topology for the Opamp. How do I decide the initial specs of the opamp to do top level(initial) simulations.

The final aim here is to design opamp for such a temp detector block.

Where can I find info/reading materal for the same. Any suggestions on books available?

thanks,

Sachin

 

[nuiscet]

A question about temperture sensor is why the lowest ptat voltage isn't almost zero? If the ptat voltage is tranfered to digital output, can you the best resolution?

 

[zenisle]

this problem is as same as bandgap

 

[amic]

A question about temperture sensor is why the lowest ptat voltage isn't almost zero? If the ptat voltage is tranfered to digital output, can you the best resolution?

I don't think it is always necessary to start with 0 V for Vptat. You can adjust your design to get whatever range you want. here i just picked up general values and coz the primary aim is to design opamp that will substract vptat from vbgr.