Maker Pro
Maker Pro

Favorite multi-channel DAC with serial interface?

J

Joerg

Jan 1, 1970
0
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.
 
N

Nico Coesel

Jan 1, 1970
0
Joerg said:
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,

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.
 
L

linnix

Jan 1, 1970
0
Joerg said:
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.

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.
 
P

PeteS

Jan 1, 1970
0
Joerg said:
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.

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
 
P

PeteS

Jan 1, 1970
0
PeteS said:
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).

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
 
J

Joerg

Jan 1, 1970
0
Hello Nico,
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.

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.
 
J

Joerg

Jan 1, 1970
0
Hello Pete,
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.

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.
 
P

PeteS

Jan 1, 1970
0
Joerg said:
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.

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.

http://focus.ti.com/docs/prod/folders/print/tlv5608.html

Just under $5 / 1k qtys

Cheers

PeteS
 
J

Joerg

Jan 1, 1970
0
Hello Pete,
LOL

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

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 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.

http://focus.ti.com/docs/prod/folders/print/tlv5608.html

Just under $5 / 1k qtys

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.
 
J

Jim Thompson

Jan 1, 1970
0
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.
[snip]

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

...Jim Thompson
 
M

Michael A. Terrell

Jan 1, 1970
0
Jim said:
We're also TV-deprived... only seven sets ;-)


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.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
J

Joerg

Jan 1, 1970
0
Hello Michael,
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.

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?
 
N

Nitro

Jan 1, 1970
0
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 <= VCC) They also have an 8 and 10 bit pin
compatable version but we have been using the 16 bit version. They are on
the pricy side.
 
R

Rene Tschaggelar

Jan 1, 1970
0
Joerg said:
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.

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

Rene
 
N

Nico Coesel

Jan 1, 1970
0
Joerg said:
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.

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

Rene Tschaggelar

Jan 1, 1970
0
Joerg said:
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.

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

Rene
 
J

Joerg

Jan 1, 1970
0
Hello Nico,
Most manufacturors have octal DACs, but all of them are
pin-incompatible despite the almost identical functionality. Work to
do be done for Jedec.

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.
 
J

Joerg

Jan 1, 1970
0
Hello Nitro,
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 <= VCC) They also have an 8 and 10 bit pin
compatable version but we have been using the 16 bit version. They are on
the pricy side.

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.
 
J

Joerg

Jan 1, 1970
0
Hello Rene,
Perhaps the LTC1665 8x8 @3.55$, or the LTC2620 8x12 @9.00$,
they are single source though.


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

Michael A. Terrell

Jan 1, 1970
0
Joerg said:
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?



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


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
 
Top