Please refer to page 6 of ADuC7122 and page 7 of ADuC7023. In respective pages it is mentioned Buffer Enabled single-ended mode (ADuC7122) and External Reference input voltage range as 0 to AVdd.
Please suggest an alternate method to use an input and output range of 5V if above maximum rated voltage operation will degrade uC and its performance.
Please suggest the best external oscillator part which can be used with above microcontrollers.
The ADuC7x2x products are rated to survive the max. rating and GPIOs can be used with external pull-up's to work on 5V I/Os. But the parts are only qualified/specified to work in a range of 2.7V to 3.6V. Outside this range the detailed parameters are not guaranteed.
As mentioned we do not guarantee any specification outside the recommended 2.7V to 3.6V operation nor do we have any quality data besides the parts survive the maximum rating.
Suppose if i go for few pins with reference 5V (if thats not possible please correct me), will the effect be the same even if use all pins with 5V reference.
Please suggest an external oscillator which will give the best results.