5V batteries

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Hi Freaks,
Does anybody know where I can find 5V (AA size) batteries with about 200-300mAh?
I have googled it and cannot seem to find one that mentions both voltage and amperage. I found 1.5V, 4.5V (not AA) and of course 9V and 12V.
Is 5V so uncommon to use?
Thanks

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5V is an odd value, as it is not a multiple of the typical cell voltage for a given chemistry.

As for AA format, it is always going to be in the ballpark of 1.5V.

Writing code is like having sex.... make one little mistake, and you're supporting it for life.

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If that is the case, then why design AVR's which have a operating supply voltage max of 5.5V (esp. for 20MHz for M48) operation? If you wanted to use something > 4.5V the next step up is 6V but it would have higher probability of frying up your AVR and/or undesirable/unpredictable performance.

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one almost never runs directly off of a battery, instead you want to stabilize the voltage to your circuit through a regulator.

Writing code is like having sex.... make one little mistake, and you're supporting it for life.

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5.5V came, I think, from the tolerance range of early IC voltage regulators (5V + 10%). Now, hardly anything is worse than 5%.

And, I think that 5V came from the voltages at which early discrete DTL and RTL logic ran well at without TOO much power dissipation and without transistor breakdown problems.It also fit, nicely, into the capabilities of early IC processes (TTL, ECL, etc). It is still with us.

Jim

 

Until Black Lives Matter, we do not have "All Lives Matter"!

 

 

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Well in case of a handheld device, I guess you would be better off using a battery. I wonder if most handheld devices using AVR's use 3.0V as their battery.

I have a pager I use which I think is an amazing design. It uses only one AA size cell (1.5V). It sucks on current consumption though. I wonder if you could design something like that with an AVR @ 1.5V VDD.

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There are AVR's that have their own built in boost regulator. These AVR's will operate at Vcc levels down to 0.7V

Writing code is like having sex.... make one little mistake, and you're supporting it for life.

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Quote:
I have a pager I use which I think is an amazing design. It uses only one AA size cell (1.5V). It sucks on current consumption though. I wonder if you could design something like that with an AVR @ 1.5V VDD.

I'm certain it contains a step up converter. Don't think this is newfangled technology. I have a walkman (yes, one of those weird electromechanical contraptions that plays TAPES) I bought in 1992 that ran from one AA battery and fairly long too.

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their so-called "gate length" (currently measured in nm (nanometers): the shorter the length, the lower the breakdown voltage) and their speed range

This may be a terminology thing, but I like to refer this as gate oxide thickness. Usually the breakdown voltage is 1/10 th the gate ox thickness (e.g. if it is 100 nm thick, then the BV is 10V) at least for CMOS.

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built-in boost regulator operates on 0.7V.

Wow the boost regulator must be having very high efficiency. Is this design similar to a switched capacitor design? Or is this achieved using inductors (as in DC-DC converters)? I would think using you would get low efficiency using inductors. I know people use on chip inductors and I have seen them being used for oscillators,PLL's etc. but not sure for these boost regulators.

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Quote:
Quote:
I have a pager I use which I think is an amazing design. It uses only one AA size cell (1.5V). It sucks on current consumption though. I wonder if you could design something like that with an AVR @ 1.5V VDD.

I'm certain it contains a step up converter. Don't think this is newfangled technology. I have a walkman (yes, one of those weird electromechanical contraptions that plays TAPES) I bought in 1992 that ran from one AA battery and fairly long too.

I used to be involved in radio paging and mobile telephone service in th mid '70s. Motorola pagers of the time were expected to run at least a month on a single N cell. The circuitry was bipolar and no boosting was done.

Tom Pappano
Tulsa, Oklahoma

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Quote:
And, I think that 5V came from the voltages at which early discrete DTL and RTL logic ran well at without TOO much power dissipation and without transistor breakdown problems.It also fit, nicely, into the capabilities of early IC processes (TTL, ECL, etc). It is still with us.

930 series RTL ICs (1960s technology) preferred to run at 3.3V - I have a piece of equipment with hundreds of the suckers in it, which miraculously still works. It runs very cool compared with TTL. If a chip ever goes bad I have no idea where I'll get a replacement, I'll probably have to program a Tiny to emulate it. RTL didn't have any diode drops and ran with a logic high of 0.7V at full fan-out. DTL, with the input diodes, needed 5V to turn on reliably. TTL was limited to 5V because that was near the breakdown voltage of the reverse emitter-base junctions at its inputs. Early CMOS could work up to 18V and just about achieve a megahertz at that voltage (though not at 5V); nowadays we have CMOS that works at 0.7V and can clock at gigahertz. Unbelievable.

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Quote:

930 series RTL ICs (1960s technology) preferred to run at 3.3V - I have a piece of equipment with hundreds of the suckers in it, which miraculously still works.

It's like why did we send a man to the moon (and back), before we could figure out putting wheels on suitcases to drag them? :)