how to use adc7..6 in ATmega8 (TQFP)

[canarybird33]

Hi
there is any special rule to use the adc[7..6] of At-mega8?
Actually when I try to use this 2 extra pins, At-mega8 is getting hot and don't works properly.

 

[ftsolutions]

You cannot violate the MAX Voltage specification on the pins - what is the voltage of the power rails o the op amp you are using, and what is the output voltage? You must make sure that you keep the voltage between GND o the ATMEga and no more than 0.5V above Vcc of the ATMEga to avoid damage. Also, for the A/D conversion to work properly, you must keep the analog voltage value between GND and the Vref voltage level to the ATMEga.

 

[canarybird33]

thanks for replay
I have considered every things you said.(MAX output voltage of opamp is 4.96).

I have used all ADCs of ATMEGA8; there is no problem when using adc[5..0] but ATMEGA doesn't work properly and gets hot when connecting the same circuit to adc 7 and adc68-O

what I'm suppose to do?:thinker:

 

[ftsolutions]

What package version of the chip are you using, the QFN, or the TQFP package (there is no ADC7 or ADC6 on the PDIP version)?

 

[canarybird33]

I'm using TQFP pakage
I read datasheet of ATMEGA8 but I couldn't find helpful informations