Hello.
I'm reading this note:
(page 4, figure 5)
and I've got some questions:
If I use a 5V Vref.... will i get 0-5v measure? will Irref be 1mA again?
How can I get aprox 0 volts at -50ºC and aprox Vref at 350ºC? How can i tune the circuit to use all the ADC's range?
Thank you very much
PD:
Page 5, paragraph 1 -- R10 and R11 set a gain of 7.47 V/V. --
I think that is a mistake. 20.0k / 3.09k = 6.47
I'm not sure because i don't now anything about opamps
PD2:
I think that the solutions of my questions is near the filter and gain stage. Changing gain and adding offset, but I don't now how.
Thanks again.
If I use a 5V Vref.... will i get 0-5v measure? will Irref be 1mA again?
Yes it looks like it to me.
I think that is a mistake. 20.0k / 3.09k = 6.47
Yes I get 6.47 as well.
I'm not sure because i don't now anything about opamps
Well you know enough to spot the gain of the inverting amplifier was wrong. 
Note that Fig 5 is not a full schematic, you will need a split power supply as well as some decoupling and a decent layout. That is don't expect it to work well on solder less bread board.
Well you know enough to spot the gain of the inverting amplifier was wrong.
Am I right? :
Note that Fig 5 is not a full schematic, you will need a split power supply as well as some decoupling and a decent layout. That is don't expect it to work well on solder less bread board.
split power supply:
I think you mean " a good Vref and GND". Can I use a 5v precision voltage reference for this circuit and for Arduino Aref?
Am I right?
Well i agree with you on the gain of that amp, so if you are wrong we are wrong together.
I think you mean " a good Vref and GND".
No a split power supply is one that has both positive and negative rails as well as a ground. This will have to be something above the Vref you want to use. Typically an op amp will have a +/- 12V supply.
MCP609 has +vcc and gnd only. Am I wrong?