Supply Voltage Issue. ATmega16 using 5.7v?

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I have planned a low cost design.

My question is if Vcc is 5.2-5.7v DC
& 20MHz XTAL.

Does The AVR works fine?

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AVR Rocks but can be Bricked too smiley

Last Edited: Mon. Oct 26, 2015 - 07:57 PM
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The specs give operating characteristics to 5.5V. Absolute maximum is 6.0.

If you can absolutely guarantee that it won;t exceed 5.7, it is probably OK. Some things might be out of spec at the higher end. For example, current drain.

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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Speed and voltage specifications listed in the datasheet:
-Mega16 goes only up to 16 MHz at voltages 4.5V-5.5V
-Mega16L goes only up to 8 MHz at voltages 2.7V-5.5V

You are violating both speed and voltage specifications, so the design is not guaranteed to work.

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Quote:

I have planned a low cost design.

My question is if Vcc is 5.2-5.7v DC
& 20MHz XTAL.

Does The AVR works fine?


No, for two reasons.

The ATMega16 is spec'd for a maximum of 16 MHz.

It MIGHT run at 20 MHz, but that is overclocking it, and it may not run at that clock frequency.

Secondly:
Although the Absolute Maximum operating voltage is 6.0 V, one doesn't generally run a Mega at > 5.5 V. (5.0 or 5.2 V would be the "normal" operating voltage).

JC

Cross post with both of the above...

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I missed the 20MHz.

Might work. Might not. I would NOT count on it for a commercial application.

Also would not count on extended operation above 5.5V for a commercial application. OK for hobby.

Jim

Jim Wagner Oregon Research Electronics, Consulting Div. Tangent, OR, USA http://www.orelectronics.net

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Are you using a zener diode as a regulator? It can be difficult to attain exactly 5 volts. You can, however, use a TL431 as a zener substitute and get exactly 5 volts.

Tom Pappano
Tulsa, Oklahoma