How did Analog Devices come to completely dominate the DDS market? - Page 1
Forum section: electronics / general

author: JoeN
author_rank: Frequent Contributor
timestamp: May 08, 2016, 07:39:58 pm
content: http://www.digikey.com/product-search/en/integrated-circuits-ics/interface-direct-digital-synthesis-dds/2556393Intersil has one DDS IC. Analog Devices makes every other one on the market. TI/BB/National never made any. Linear never gave it a shot. It just interests me because I can't think of any other IC category where one manufacturer does the whole market and no one is trying to take it away from them. Anyone know why that is?

author: chris_leyson
author_rank: Super Contributor
timestamp: May 08, 2016, 11:11:22 pm
content: Because it's a small niche market

author: Bud
author_rank: Super Contributor
timestamp: May 09, 2016, 04:47:45 pm
content: That is for mass market. I attended a Keysight seminar the other day where they said they use their own DDS for their arbitrary waveform generators. That DDS may never see the world ouside of Keysight.

author: JPortici
author_rank: Super Contributor
timestamp: May 09, 2016, 06:33:19 pm
content: well you can always make one with an fpga or mcu (if dma can output to a parallel port, like in pic32 for example)... or even with glue logic (oscillator, counters, latches, parallel memory)

author: coppice
author_rank: Super Contributor
timestamp: May 09, 2016, 08:09:40 pm
content: There were several companies making DDS chips in the late 80s and early 90s, although they generally didn't integrate the DAC. I've used direct digitial synthesis in many designs, but I only once ever used a DDS chip. Times change, and there isn't really a thriving market for a chip that does something as elementary as DDS. People are most often looking for a really good DAC to accept the DDS signal coming out of some much larger functional hardware block.

author: JoeN
author_rank: Frequent Contributor
timestamp: May 10, 2016, 01:41:33 am
content: Quote from: JPortici on May 09, 2016, 06:33:19 pmDoesn't that give you a pretty nasty step wave? Can that be filtered into a quality sine wave easily? Also, a good DDS gives you a pretty huge frequency range, good selectability of frequency (48 bits is typical) and pretty good quality of the sine wave. Can you roll your own and keep this flexibility? I don't know a lot about this so I ask.

author: sarepairman2
author_rank: Frequent Contributor
timestamp: May 10, 2016, 02:26:01 am
content: They are great. Let's say you want to design a analog front end that does not raise the bar, you just need a fairly complicated solution to a expensive problem.Do youa) spend insane amounts of development time writing, debugging compiling software? this often means alot of learning, porting from one system to the next, dealing with all the harrows of software developmentb) take an off the shelf chip and communicate to it using SPI_WRITE commands?The bigger of a company you are (or super genius) the more sense it makes to "roll your own". If you are a small company or one guy, do you want to get blogged down with this ? How often do you need specifications that exceed a nice DDS chip?If you make your own anything then it will probobly be better, because a customized solution is ALWAYS better, since there are always design trade offs. However, a DDS chip will let you "get on with life" and leave your hair intact.

author: Skimask
author_rank: Super Contributor
timestamp: May 10, 2016, 02:27:08 am
content: A really fast counter, a quarter wave sine table, a good DAC, a flexible filter, and a bazillion dollars, and you're the next AD.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 10, 2016, 05:05:33 am
content: A big market for DDS is motor drives and other inverters, but those use PWM or Delta Sigma rather than a traditional DAC. Most common is to just use a microcontroller programmed to operate as a DDS, although some high end drives use FPGAs or ASICs.DDS is also used a lot in digital radio, but those are mostly purely in the digital domain and is therefore part of the ASIC or FPGA used to implement the radio. The local oscillator for the RF front end is typically a conventional PLL as few need the adjustment range offered by DDS.

author: coppice
author_rank: Super Contributor
timestamp: May 10, 2016, 05:25:37 am
content: Quote from: JoeN on May 10, 2016, 01:41:33 amThe quality of the final sine wave, if your DDS is actually producing an analogue signal (most don't), is purely determined by the quality of the DAC and the post filtering you use. ADI's DDS chips don't contain better DACs than they sell as stand alone DACs. In fact, you have a much better choice of parts as stand alone DACs.Why would anyone have a problem constructing two 48 bit registers (the accumulator and the increment register), a 48 bit adder, and a sine wave lookup with enough bits to match their DAC?

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: May 10, 2016, 08:44:24 pm
content: I think I can explain the divergence of opinion on whether analog's DDS line is niche market or not on the fact these DDS chips have a fairly high profile amongst hobbyists. Lots of little hobby projects and simple function generators. It is like that popular Exar chip the XR2206 function gen. Hobby projects galore and high demand from digikey from buyers that buy 1 and then go away. From the Exar website: "Product Discontinuance of XR2206. Discontinued due to low market demand"

author: JoeN
author_rank: Frequent Contributor
timestamp: May 11, 2016, 03:17:17 am
content: Quote from: chickenHeadKnob on May 10, 2016, 08:44:24 pmAnalog has a very small number of DDS parts that I would call hobbyist friendly (e.g. the AD9850). Many of the others look more difficult, expensive, and faster parts that seem to be designed for quick frequency hopping and high frequency signals.

author: NiHaoMike
author_rank: Super Contributor
timestamp: May 11, 2016, 04:08:18 am
content: Quote from: blueskull on May 10, 2016, 02:34:31 pmA microcontroller programmed to cycle through a sine wave and output it on PWM *is* a DDS.The drives using FPGAs or ASICs use something other than classical PWM to lower the effective switching frequency. They're typically only found in high power applications like EVs.