Dac - 16 bit; 0-5V

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I am looking for 16 bit dac & 16 channel with 0-5V.
Also application is battery powered, so I need DAC to put in sleep when not required.

I had found this octal dac;low power from TI DAC8568 with SPI interface.

Its 8 channel so I need to use two dacs in parallel. But I didn't find CS pin there. 
Is there any other alternative to use 2 dacs in parallel . I have only one SPI in my MCU.

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Can't you use /LDAC in a manner similar to CS?  (I seem to recall threads about similar interfaces.)

 

 

 

I have only one SPI in my MCU.

What MCU is that?  Modern AVR8 models have USART-as-SPI-master  functionality.

 

An interesting app, with that many channels and that precision.  "DAC" implies to me that "something is being driven".  Let's say 4.096V output reference for discussion.  With a 12-bit DAC, that is a millivolt per count.  With a 16-bit DAC, that is 250uV/count.  Your bank of 16 output devices will really care if the voltage seen is 3.456V or 3.457V ?  Or 3.4567V vs. 3.4565V ?

 

I went to DigiKey and found over a dozen listings for 16-bit/16 channel DACs.

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

Last Edited: Sat. Mar 7, 2015 - 03:48 PM
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@theusch , I think nLDAC is loading the output dac. I think its sort of enable/disable pin.

 

I need all 16 dac to be operating.

 

Yes I found one 16 bit dac/16 ch from AD. But I had selected this as it is low power & can work upto rails.

 

I am using some other company MCU, it has only one SPI

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I think its sort of enable/disable pin.

What does the datasheet say?  How is it different than chip-select?  SPI data arrives on the pin, but is only latched if you  use the LDAC.  So your second unit would see the values stream by, but never load them.

 

You've expressed the 16 channel, 16-bit need but not gone further.  I've done load cell apps, where ADC pretty much needs to be 16 bits or more.  But for DAC?  Perhaps it is the same as ADC/loadcell:  need extra bits to "absorb" the noise?

 

If this device is important to you, then experiment with multi-dropping.  And/or look at microcontroller interfacing code examples found on the 'Web.  And drop a note to TI--if you would have done that when you started this thread you might well have a response by now.

 

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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@theusch , nSYNC is CS pin here.

I will start post on TI forum also for dual interfacing.

 

I have customer requirement about 16 bit adc. We don't know end application. Its requirement I have to make interface only.

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I have customer requirement about 16 bit adc.

Did you mean DAC?

 

Either way, IME there is a lot more to picking out an ADC than just the number of bits.  Somewhat the same with a DAC -- reference source; signal drive; ...

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Yes I mean't dac.

Thanks for your comments. 

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So your customer didnt give you any requirements so you could create a design? He just picked a dac chip and a microcontroller he liked. Is it a firm fixed price contract? How do you know when you are done? Does he provide an acceptance test? (That might be the performance requirements we are looking for.... something like "Hook up the scope and make sure there are 16 channels of 16bit waveform each channel updating every ms" or something like that).

 

Imagecraft compiler user

Last Edited: Mon. Mar 9, 2015 - 10:07 PM
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No clear written requirements = Contract terms are Time and Materials (T&M).

Not how's. Just what's.

Monthly invoices.

Last Edited: Wed. Mar 11, 2015 - 04:49 PM
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A thread very similar to this was started a month or two ago, and bugger if I can find it.

Jim

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