Harvest diodes and transistors. They can also be used as thermal sensors - I've made and calibrated one.
" Ok! How do you wire it? "Google is your friend: https://www.google.ca/search?q=transistor+temperature+sensor&client=safari&hl=en-ca&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjYs-zcupnuAhVgGDQIHQpaC3IQ_AUoAXoECCEQAw&biw=1269&bih=834&dpr=2
...instead of a reverse biased diode...
So you are now using the 1.1 V internal reference, are you not?