DAC for Audio 48kHz 24bit without software control - Page 1
Forum section: electronics / beginners

author: Chaos_Klaus
author_rank: Contributor
timestamp: November 04, 2015, 04:24:42 pm
content: Hey folks,I have a chip that decodes an ADAT-Stream into 8 channels of digital audio at a 48kHz and 24bit. Now I need suitable DACs to get 8 channels of analog audio.All the ICs I found are pretty complicated and have all these features that I don't need. The packages that feature 8 channels are very fine pitch and they require writing the settings via SPI or I²C.I would rather not add a micro controller to my project only to write some stupid settings into the IC. However, I can not really find any 24bit DACs that have hardware control. Are there any? Am I just blind?I don't really care if it is one 8 channel package or 4 two channel ones.Any Ideas?Thank you for your time. I only ask this because I've been searching for quite some time now, without success.EDIT: Oh, I am in Germany by the way. Chips from TI are usually quite expensive around here. The largest producer of semiconductors in europe is STmicroelectronics and their equivalent chips are way cheaper. But I don't really care if I have to buy a relatively expensive chip, if it comes to that.

author: dmills
author_rank: Super Contributor
timestamp: November 04, 2015, 05:10:52 pm
content: PCM1781?There are loads of two channel parts that have hardware control (at least over the basics), some are dual mode and can be put into a software controlled mode as an alternative.The TI selection ishttp://www.ti.com/lsds/ti/audio-ic/audio-dac-product.page?familyAliasId=1200582#p1341=H/WI would note that MCLK is critical to the performance of these things and that a VCXO rather then a VCO for the PLL can be a good thing.For audio, TI is the elephant in the room, together with the crystal semi stuff, akm have some interesting things but sourcing in small quantities can be problematic.Regards, Dan.

author: Chaos_Klaus
author_rank: Contributor
timestamp: November 05, 2015, 11:57:52 am
content: Unfortunately, the 1781 only features 16bit/24bit I2C or 16bit right justified input. I can only generate left or right justified 24bit data streams.The PCM1681 could do the job, but I can not find it with any of the suppliers (that I know) here in germany.EDIT: I just noticed that the PCM1681 needs 3.3V digital supply in addition to 5V analog supply. I don't want to add another (3.3V) supply rail to my project, so that IC is out. :[

author: dmills
author_rank: Super Contributor
timestamp: November 05, 2015, 01:01:43 pm
content: Pretty much **NOTHING** LSI these days does 5V digital, it is all at most 3.3V, and many things are very much lower then that.There are plenty of parallel configuration parts out there, but 5V only is a big ask these days, just stick a 1117 or such in there to produce 3V3 if you have to, it opens the field right up.Regards, Dan.

author: Alex Nikitin
author_rank: Super Contributor
timestamp: November 05, 2015, 02:11:21 pm
content: The CS4345 should be OK for all your requirements (a single 5V supply, 24 bit Left- Justified, hardware configured), it isavailable from Digikey at $3 each. Or, if you want something decent and can spend considerably more, find the CS4396 or CS4398 (should be available, but not cheap).CheersAlex

author: Chaos_Klaus
author_rank: Contributor
timestamp: November 05, 2015, 03:12:10 pm
content: Oh well ... why do these things have to be so expensive? ... even if the specs look so terribly '90s.

author: AndreasF
author_rank: Frequent Contributor
timestamp: November 06, 2015, 10:36:13 am
content: What about old Wolfson parts (now also owned by Cirrus)? E.g.https://www.cirrus.com/en/products/wm8761.html

author: Chaos_Klaus
author_rank: Contributor
timestamp: November 08, 2015, 10:28:37 am
content: I think I might even go for the CS4335. It's cheaper, larger pitch (which means I can etch the PCB myself) and I think I don't need all that dynamic range anyway.