Favorite multi-channel DAC with serial interface?

Hello Folks,

What is your favorite DAC if you have to set a dozen or more DC voltages via a serial bus? Of course, ideally it should be cheap, multi-sourced, available from a couple of big suppliers (ahem, no vaporware...). 8-10 bits ok, or more. External ref preferred unless the internal one is really good. Speed does not matter at all.

The bus type is still open. Guess I2C is favored for non-star architectures but in the end it doesn't matter much as long as the protocol is easy on the SW guys.

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Regards, Joerg

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Reply to
Joerg
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Multi sourced? That's a tough one. I doubt you'll find even one 8 output DAC. Personally, I like the AD5318 from Analog. It can use 2 references.

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Reply to
Nico Coesel

I would do it with A2D and PWM adjusted LM317. We need the D2A (317) for our A2D sensors, but there's no reason why you can't use the A2D for your D2A. A micro with A2D can do I2C, 232 and/or USB (or some other 3 letters words). You can set external analog reference with the micro. Most micro can do 10 bits with internal ref with good result.

Reply to
linnix

Hi Joerg

Most A-Ds max out (standard ones, anyway) at 8 channels. For a low cost easy to use part, I tend to use the National ADC08* series. There is a

16 channel device, but it's parallel and more expensive.

If you can live with 2 devices I'd use the ADC088S022. $1.31 / 500 budgetary. Separate reference input for the converter. The 8 bit device is about $5 in the same qtys. (I have 2 of these in a current design for system voltage monitoring).

I seem to recall a number of others make the ADC08* series, but I might be wrong. On the other hand, I have not had problems getting the parts from National.

SPI style interface on this part - uses a CS, so providing you can generate separate CS outputs from the controller, you can have as many as you like.

Cheers

PeteS

Reply to
PeteS

That should have read:

'The 16 channel device is about $5. The ADC088S022 is 8 bit, slow but it works.SAR style, so if there's noise (which I doubt from your description) you'd need some extra filtering. This thing is as old as the hills and it's still going strong.

Cheers

PeteS

Reply to
PeteS

Hello Nico,

Well, there are octal DACs with a serial port, for example the TLC5628 from TI. Around $2.50. However, since I rarely need such parts I don't know whether it is or may become a mainstream device.

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Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

Hello Pete,

Thanks. That info might come in handy for a future design but this time I need a DAC ;-)

I2C might be better but I could certainly make SPI work here. I'd just have to beg some more port pins for enough CS lines off the digital folks. Maybe a box of chocolates would help in the "convincing process". But then again a dozen or so devices would only need three CS bits.

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Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

LOL

That'll teach me to read newsgroups and watch TV at the same time

That said, there isn't much of a choice for multiple DACs. given my preference in suppliers and the fact you aren't looking for 'DSP quality' outputs, I'd take a TI device. I used the TLV5608 a little while ago and it was nice because of the separate digital and analog supplies.

formatting link

Just under $5 / 1k qtys

Cheers

PeteS

Reply to
PeteS

Hello Pete,

Well, if the ball game was good then it was worth it. We are TV-deprived but happy with it. Only a dozen channels and half in Spanish, one 25" TV inside and a 13 incher on the deck, that's it.

That looks like a great part and allows external ref which is good. It seems to be over $5 on the market right now but in this project that isn't a big issue (that's kind of nice for a change).

I2C would be nicer because I could hang all kinds of other feedback stuff on it. But I feel uneasy designing one in from a EU company. Got burned too many times by botched delivery attempts.

--
Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

[snip]

We're also TV-deprived... only seven sets ;-)

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
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Reply to
Jim Thompson

Me too, and I've already given away three more. Two get turned on once in a while, and the others aren't even plugged in.

Oh, yeah, I also have one of the first Motorola Quasar "Works in a Drawer" solid state color TVs made in the mid '60s and it still works. That makes eight.

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Reply to
Michael A. Terrell

Hello Michael,

Brings up a point discussed a while ago where someone said something about new TVs except for very small ones being required to contain a digital tuner. Well, a few weeks ago at Costco I looked. The label for a

20" set explicitly said analog tuner, a 24" set did not mention a digital tuner (while all the really big ones did). So, is digital TV sliding?
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Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

Hi,

I did not see it mentioned, We have had good luck with the Linear LTC2600 8-channel 16 bit SPI interface DAC, 2.5 to 5.5 with rail to rail drive. External ref or use VCC. (external ref is the max vout and must be

Reply to
Nitro

Perhaps the LTC1665 8x8 @3.55$, or the LTC2620 8x12 @9.00$, they are single source though.

Rene

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Reply to
Rene Tschaggelar

Most manufacturors have octal DACs, but all of them are pin-incompatible despite the almost identical functionality. Work to do be done for Jedec.

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Reply to nico@nctdevpuntnl (punt=.)
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Reply to
Nico Coesel

The LTC1665 8x8 for 3.55$ and the LTC2620 8x12 for 9.00$ come to my mind. Both single sourced though.

Rene

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Reply to
Rene Tschaggelar

Hello Nico,

Yes, and they are mostly SPI so maybe I2C isn't the thing anymore to push in cases like this. Even though it would be perfect here. I was taken aback by the fact that Philips doesn't offer much as the parent of I2C. Could only find some audio converters.

Waiting for JEDEC to fix the turf wrestling would be like waiting for an EDIF standard for schematics which IMHO is never going to happen. So, maybe each device needs 2-3 positions with only one being occupied, depending on which DAC is purchased.

--
Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

Hello Nitro,

Thanks for the hint. Looks like I'll go with an 8-ch SPI version because they seem quite prevalent. The LTC part shows no stock at Digikey which raises a bit of a flag here. But the TLV5608 from TI is in stock.

Take a look at the AD5391: A whopping 16 channels.

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Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

Hello Rene,

Thanks. They look good. Although the numbers in stock at Digikey are really low which in the US is often considered the "popularity barometer".

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Regards, Joerg

http://www.analogconsultants.com
Reply to
Joerg

I hope so. I don't plan on buying one.

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Reply to
Michael A. Terrell

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