Voltage Convertor Pcb.

Would you be interested in buying a Level Convertor Board at: 25USD

  • YES

    Votes: 0 0.0%
  • NO

    Votes: 0 0.0%

  • Total voters
    0

ashaw

Still Fresh
Joined
Jul 1, 2008
Messages
35
I have Designed and priced a voltage convertor PCB it has the following properties:

1/ MAX1722, Step up convertor, switchable between 3.3 and 5V
2/ TXB0108, 8 Bit Level convertor, Though t keep the board size doen only 6 bits of conversion are available
3/ LP3990TL 1.8V regulator, Needed for the level convertor,

The board has the form factor of a 16 pin SPDIP that is 572mil x 390 mil (14.6mm x 10mm)
There are cheap sockets for this form factor available from Digikey.

The Schematic diagram and layout used can be found at:

http://www.alexisshaw.com/voltageconvertor3.pdf

Gerber files can be ound at:

http://www.alexisshaw.com/Gerbers.zip

A price breakdown for different quantities can be found at:

http://www.alexisshaw.com/BOM.pdf

Please comment on the layout and reply if interested.
 
this board takes the 2.8V out of the EXT port and gives you either 3.3V or 5V
It also converts the 1.8 IO voltage levels out of the UARTs and gives you either 3.3V or 5V IO levels.

to get $25 I need 100 orders, $20 - 200, $15 - 500. this is at cost price, without shipping, straight off the quotes.
 
'lulzfish' said:
I need to do what this board is for first.
EDIT before actually even posting: ashaw beat me to it :), but:
I fail to fully understand this sentence but if "What is this board for?" is equal, then:
It's a board to allow easy usage of the GPIO's/UART's and power source on the pandora's EXT port by converting the 2.8V power and 1.8V signal levels to 3.3V or 5V power and signal levels.

@ashaw:
And i just voted yes on 15 and 20 USD but no on 25 USD. Sorry for that - i was thinking with the USD=EUR mindset again (duh). 20 EUR is my limit so it would be yes for 25 USD, too.

And may i say that the design is quite nice if it works. Though i got a little bit of "I've seen these names before" at the schematics :p. Not a problem - just go ahead, but note: I used EAGLE's +UB on the 2.8V line just on the lack of a better ready to go name (in the supply library) and because it might change depending on the configuration of the OMAP's companion power chip on the pandora. So its not really "battery voltage" (what somebody might think).

I'm waiting interested on the results of this poll now...
 
Last edited by a moderator:
Note to all I am trying to gauge interest in this product, I there Is not enough interest i simply will not go ahead with production, which would be a shamefull waste of time for me, but at least I am not bankrupting myself in the process, I would not make any profit on these boards, but as I am not going to use these myself in the near future and because of the financial crisis I cannot afford to make a loss either.
 
Next (obvious) question after: "What it is it?"

'Where can I use it for in the Pandora?' (yes I know you can change the Volt values with it, but why do you want to use it?)
 
Last edited by a moderator:
If you are intending on making any mods for the Pandora that you want to attach to the ext port, then you need to adjust the voltages as a lot of "hobbyist" stuff like Atmels don't work too well at 2.8V VCC and 1.8V signal levels. So your choice is to either use one of these boards, or incorporate the same kinda thing into your designs.

If your not planning on doing any mods (or using someone else that doesn't contain the necessary level translation), then this board is no use to you.
 
Last edited by a moderator:
I have a suggestion if that's okay. I'm assuming this board's only purpose is to connect to the EXT port on Pandora. If not, some of this might be unnecessary.

Perhaps U3 should be powered from Vin? It will be more efficient to use the Vin from EXT port because it is no more than 3.0V whereas Vcc is 3.3V or 5V. Also, since the logic level (1.8V) needs to be present any time the EXT port is active, the 1.8 EN pin could be tied to Vin. You can shut off Vin through Linux on Pandora at any time so voltage control is always present without needing an extra GPIO. As long as the TXB0108 is the only thing connected to the EXT I/O pins, they are protected from a live system on the secondary side (which won't happen if the secondary side is completely powered by Vcc).

C1 and C2 are listed as 47uF in the schematic but are 10uF in the BOM. I was seeing if you were choosing a part with a low ESR which you have, but the capacity is different. Just choosing what was in stock to buy?

If you get lots of buyers on something like this, adding an RS-232 converter for UART3 would be nice, even if you don't populate the footprints. The kernel uses UART3 as its console and I think others will be interested in that too. I'm sure it keeps making your small board bigger so you can probably ignore this but if you do more polls, you could see what the interest from others will be.
 
Last edited by a moderator:
If I get a lot of people interested than I will use the one at the top of the page

Otherwise I want to make this board as flexible as possible.

if the efficency of the regulation is a problem they can simply turn off the regulator and add their own though and it increases the flexibility of the board.

Oh and about the capacitor, it seams i re-used a bit too much. I will of cource correct this very serious mistake.
 
gerbers and others replaced with improved PCB with corrections noted by MWeston and also including his suggestion of a 1/1 RS232 tranciever.
 
Back
Top