SV: Re: SV: Re: [sdiy] 16bit DC, DAC, SPI!

[karl dalen]

Most of these resistor sting DACs has hillarious INL, DNL ,
Ti has some that swings +/-64bits even on 12 bit devices
and thats not good.

I just found a R2R based device AD5062,(its actually a 12 bitter with
some neat solutions for the MSB's) its fairly cheap, unfortunately
the reference is external SOT23-8 package, easy to solder! ;-).
4uSc update rate,plenty of time to do hundreds of CV's.

But i dont like this external reference idea, its just an argument for
the suspects to sell more sillicon.

KD




--- Eric Brombaugh <ebrombaugh at earthlink.net> skrev:

> Bruce Duncan wrote:
> >> The LTC1655 looks pretty nice. I've also got an application that uses 
> >> the LTC26x4 quad SPI DAC. They're around $5-$10 (non-stock @ Digi-Key 
> >> however) depending on resolution (12, 14, or 16). Small package, but the 
> >> SPI clock rate is 50MHz so you can use them for fast sample rates. Plus 
> >> the DNL is better than 0.2LSB on the 16-bit part!
> > 
> > Isn't it the accuracy or Integral Nonlinearity in LTC speak that is the 
> > more important spec for DC.
> > In the LTC1655 case it is +/-8 LSB same as the AD5663
> 
> Yes, INL is a critical parameter. The worst-case for the LTC1655 gives 
> it only 11.5 bits accuracy (13-bits typical). The AD5663 seems to call 
> this 'relative accuracy' and worst-case boils down to 12 bits (13 bits 
> typical). For the LTC26x4 its max range limits the part to more like 
> 10-bit accuracy worst case (14-bit accuracy typical).
> 
> So it looks like the AD5663 comes out ahead worst-case. Available in 
> single quantities from Digi-Key for $8.83. Main downside is ~200kHz 
> sample rate (no biggie for CVs) and 10-pin MSOP package.
> 
> For small SMDs in SDIY applications I've had good luck with DIP - 
> MSOP/SSOP adapters - once you've done one or two of those you'll get the 
> hang of it and they come out nice and clean. You can get the adapters 
> from Mouser in panels and just snap them off as you need them. Google 
> Bellin Dynamic Systems for part numbers.
> 
> Eric
> 



	
	
		
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