At less than $0.80 each, these little boards are fantastic. The 3A rating
is intermittent duty cycle, efficiency is excellent, and protected from
output short-circuit/overload:

I power Raspberry Pi 3 boards, etc., from these. They don't skip a beat:

There are clearly a few items of ebay electronics about which some fear, uncertainty and doubt is in order.

For example, good luck getting 20 AH at 12v out of this:
?? ?? ( )

Or getting the maximum rated amps out of any $2 switching (or linear) power supply
across the entire claimed input and output voltage ranges. ??Or even half of the rated amps.
For more than a few milliseconds.

Ebay RD16HHF1 RF power FET's are often some random switcher FET with fresh ink.
That can even happen with the relatively cheap IRF510, why anybody would bother is beyond me.

But many have had surprisingly good luck with the $3 Nano's.
Including most Bitx40 owners.
Though they must be cutting corners where they can off the design of the $30 original.
??
And I did just order 50pcs of the AD8307 for less than I could get two out of Mouser
as per the last paragraph of this post: ??/g/BITX20/message/32675 ( /g/BITX20/message/32675 )
Got my fingers crossed.

Jerry

On Sun, Oct 22, 2017 at 02:40 pm, Arv Evans wrote:

Regardless of what has been said about the on-board regulator being
questionable, it is a pretty
standard 3-terminal regulator it is usually good for at least 100 ma.?? I
have used a couple dozen
of the Asian manufactured NANO boards with +13.6 volts input and they all
worked just fine.????


I suspect that your concern about exceeding current limits may be valid
though because there is
no heat sink on those on-board regulators.?? Most of my Arduino based test
equipment uses the
on-board regulator for NANO and an attached LCD.?? Other circuitry is
powered from a 7805L or
higher current capable 7805 equivalent.??


There is a lot of not-invented-here and not-manufactured-here sentiment
among the ham radio
fraternity.?? Some of it justified and some is just myth and FUD (Fear,
Uncertainty, and Doubt).

Regardless of what has been said about the on-board regulator being questionable, it is a pretty

standard 3-terminal regulator it is usually good for at least 100 ma.? I have used a couple dozen

of the Asian manufactured NANO boards with +13.6 volts input and they all worked just fine.??

I suspect that your concern about exceeding current limits may be valid though because there is

no heat sink on those on-board regulators.? Most of my Arduino based test equipment uses the

on-board regulator for NANO and an attached LCD.? Other circuitry is powered from a 7805L or

higher current capable 7805 equivalent.?

There is a lot of not-invented-here and not-manufactured-here sentiment among the ham radio

fraternity.? Some of it justified and some is just myth and FUD (Fear, Uncertainty, and Doubt).

Nope they didn't survive because the failure of the regulator meant that, when they blew, they went short circuit and slammed full 12V onto the Atmega.
The ones that I have had fail were all fitted with supposedly genuine (ha ha ha ) AMS1117-5 5V versions of the regulator.
Luckily the problem was dealt with by me before the product went to the client by the simple expedient of kludging a better 5V supply and ignoring the Nano regulator completely.
As an aside I puchased a few sacrificial batches of Chinese AMS1117-5 regulators and found that, on test, less than 50% were capable of handling more than 9V input safely.
Some manufacturers claim an input of <=12V while other claim 15V.
The joys of the game.

Dale G4IPZ


----- Original Message -----
From: Dexter N Muir
To: [email protected]
Sent: Sunday, October 22, 2017 9:24 PM
Subject: Re: [BITX20] I made a mistake


Dale me ol' Chin-wah, commiserations - though if the rest of the chip survives you'll have a ready stock of Nanos to hand! That flaky reg is the reason for the Raduino's 78LM7805 regulator - that and the Nano's current drain being either too close to or over the max spec of a 78L05.
p.s. I've taken my 7805 to the other face of the PCB for heatsink clearance and accessibility. It allows me to sit stuff close to that side of the Raduino

David KB4FXC

Regardless of what has been said about the on-board regulator being
questionable, it is a pretty
standard 3-terminal regulator it is usually good for at least 100 ma. I
have used a couple dozen
of the Asian manufactured NANO boards with +13.6 volts input and they all
worked just fine.

I suspect that your concern about exceeding current limits may be valid
though because there is
no heat sink on those on-board regulators. Most of my Arduino based test
equipment uses the
on-board regulator for NANO and an attached LCD. Other circuitry is
powered from a 7805L or
higher current capable 7805 equivalent.

There is a lot of *not-invented-here* and *not-manufactured-here* sentiment
among the ham radio
fraternity. Some of it justified and some is just myth and FUD (Fear,
Uncertainty, and Doubt).

Arv K7HKL
_._


On Sun, Oct 22, 2017 at 3:11 PM, David McGough <kb4fxc@...> wrote:

Hi Dale,

I'm designing a NANO project right now that uses the on-board regulator at
about +12v input. I'm only powering the atmega328p chip and 6 digital
outputs, consisting of low-current LEDs/opto-isolators. I've had no
problems, so far, with a random sampling of about a dozen cheapo
boards....My max current draw is perhaps 25mA. How much current were you
drawing from the regulator where it popped??

....Now I'm concerned that I may need to consider an external regulator.

Thanks,

73, David KB4FXC

I'm designing a NANO project right now that uses the on-board regulator at about +12v input. I'm only powering the atmega328p chip and? 6 digital outputs, consisting of low-current LEDs/opto-isolators. I've had no problems, so far, with a random sampling of about a dozen cheapo boards....My max current draw is perhaps 25mA. How much current were you drawing from the regulator where it popped??

....Now I'm concerned that I may need to consider an external regulator.