Anybody recommend a 10 bit DAC? - Page 1
Forum section: electronics / projects

author: Aodhan145
author_rank: Frequent Contributor
timestamp: March 05, 2015, 06:47:24 pm
content: Hi, I'm currently looking for an i2c 10 bit DAC with a Vrefpin and 2 address pins. If possible DIP or larger SMD. Does anybody know a chip with these specifications?Thanks in advance.

author: Anand
author_rank: Contributor
timestamp: March 05, 2015, 06:56:45 pm
content: Sorry, what doesQuote from: Aodhan145 on March 05, 2015, 06:47:24 pmmean?

author: Aodhan145
author_rank: Frequent Contributor
timestamp: March 05, 2015, 07:10:17 pm
content: Like A0, A1 to control the i2c address.

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: March 05, 2015, 07:24:12 pm
content: I've used theMCP4725.. It has 1 address pin, and is 12 bit. VRef is from the supply. With 10 or 12 bits, an accurate VRef pin does not make much sense.

author: Aodhan145
author_rank: Frequent Contributor
timestamp: March 05, 2015, 07:27:18 pm
content: I was actually looking at the MCP4725. I need to put three in a circuit any ideas how to achieve this with it?

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: March 05, 2015, 07:31:28 pm
content: Quote from: Aodhan145 on March 05, 2015, 07:27:18 pmIt's more economical then to use theMCP4728. I've used that alsoIt has internal and external VRefedit: notice the package, I made a mistake with this first time I used it

author: Aodhan145
author_rank: Frequent Contributor
timestamp: March 05, 2015, 07:38:56 pm
content: Thank you very much. This is perfect this will save me routing SOT23-6 packages. I'm making the pcb my self and its not always the best it makes routing these a lot harder.

author: mikerj
author_rank: Super Contributor
timestamp: March 05, 2015, 08:24:03 pm
content: Quote from: JohnnyBerg on March 05, 2015, 07:24:12 pmResolution and accuracy are completely separate things. We have many products that use 12bit DAC that require very stable references.Quote from: Aodhan145 on March 05, 2015, 06:47:24 pmDo you need separate DACs or could you use a single DAC package with multiple channels?

author: tszaboo
author_rank: Super Contributor
timestamp: March 05, 2015, 08:29:14 pm
content: Quote from: mikerj on March 05, 2015, 08:24:03 pmWith 0,4mA power supply this thing needs, you can power it from the 4,096 or 5V reference directly. I2C is good for this.

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: March 05, 2015, 08:46:24 pm
content: Quote from: mikerj on March 05, 2015, 08:24:03 pm±0.2 Least Significant Bit Differential Nonlinearity (typical) at 12 bit ?

author: Aodhan145
author_rank: Frequent Contributor
timestamp: March 05, 2015, 08:53:22 pm
content: Single might of been better but I can use multiple in one package

author: Liv
author_rank: Regular Contributor
timestamp: March 05, 2015, 09:53:34 pm
content: 10 bit 4-channel AD5315 or 12 bit AD5625.

author: Christe4nM
author_rank: Unknown
timestamp: March 06, 2015, 08:49:13 pm
content: You need to know the following to be able to decide if an ADC or DAC fits your application. I'm really wondering why nobody else asked these questions. To me this is 'choosing a data converter 101'. So here goes:* Do you need the output to be at precisely 10 bits in resolution, or is less also OK. In other words: do you want 10 effective bits of resolution (ENOB), or take a 10b DAC knowing that you might end up with only 8-9 usable bits of resolution?* What is the highest frequency of the output signal of your DAC? If you use it need mostly for DC signals, then how fast should it respond to a step in the output?* At what conversion rate do you want the DAC to run? At least 2x the highest frequency of you desired signal, but 5x times is already at lot better. Also 10bits at 100MSPS is something quite different than 10 at 1kSPS. The inverse of this question is: what is the maximum settling time the DAC can have per conversion of a sample?* Depending on the above: what kind of DAC topology would suit your application the best?If you want to go deeper:* What kind of linearity do you require of the DAC? (Error margin in INL and DNL)Now that these questions answered you can look for a DAC that fits those requirements and has I2C and the additional stuff you require.

author: mikerj
author_rank: Super Contributor
timestamp: March 26, 2015, 10:54:52 am
content: Quote from: JohnnyBerg on March 05, 2015, 08:46:24 pmDNL and INL are separate issues to reference stability, and are irrelevant for plenty of applications. e.g. we use DACs to control the currents into the various sections of a tunable laser. The overriding priority here is that, once set, the currents remain stable over temperature and life which requires a decent reference. A poor DNL or INL performance doesn't really matter in this case.