mixed_signal wrote on Feb 6th, 2012, 8:29am:Thank you all for the valuable information!
I have to design the voltage reference as well for the sensor.
I am using a process where the max voltage Vdd is 1.2v and the bandgap voltage is slightly <1.14V. Is it advisable to go for voltage mode band gap reference where I will have vref=1.2v with few mV overdrive for my PMOS.
Will current mode bandgap be a better option? Is it suitable for sensor with uncalibrated accuracy? Since resistors in current mode is large I am wondering about the offsets and the inaccuracy.
You can not do a traditional bandgap with a 1.2V supply. I'm a tad worried that you are taking on a such a challenging task and not knowing that as there are many more pitfalls that are much more subtle. Anyway, getting the tolerance you need with a current mode bandgap (like Banba) will be tough at the power levels you are dealing with. Watch process corners and mismatch in your current mirrors. There are far better ways to do this than with a full bandgap, but I'm a contractor (and Jerry is too) and bandgaps/temp sensors are a big part of my "mental inventory" so I don't want to give any more hard earned information away for free. Sorry....
Jerry - the 1st order incremental is basically a refined version of the vco-type converter. I remember a paper about temperature to frequency converter that may have used that being published a few years back, so the OP might be able to find it (there I go giving it away again) :)
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