EEVBlog #805 - Siglent SDG2122X Arb Generator Teardown - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: October 07, 2015, 10:47:49 pm
content: The new Siglent SDG2122X X-Series Arb Signal Generator TeardownNow in 4K resolution option.Trio Test & Measure:http://www.triotest.com.au/shop/function-generators/3820-siglent-sds2024x-40mhz-2-channel-arbitrary-waveform-generator-1gsas.htmlDatasheets:http://www.ti.com/product/am3352http://www.analog.com/media/en/technical-documentation/data-sheets/AD9122-EP.pdfhttp://www.ti.com/lit/ds/symlink/ths3095.pdfhttps://www.altera.com/content/dam/altera-www/global/en_US/pdfs/literature/ds/en2342qi_09520.pdfhttp://www.ti.com/lit/ds/symlink/opa695.pdfhttp://www.analog.com/media/en/technical-documentation/data-sheets/AD8510_8512_8513.pdf

author: Armxnian
author_rank: Regular Contributor
timestamp: October 07, 2015, 11:37:56 pm
content: Is this 1080 upsampled to 4k during your render?

author: lukier
author_rank: Unknown
timestamp: October 07, 2015, 11:44:37 pm
content: Good teardown, thanks for taking the trouble to decode all the parts in the vital parts of the device. I've spotted DAC8580 (designator U27) I think, this will be probably auxiliary DAC for the offsets. Pretty decent in it's own right, 16 bit monotonic, 16 MSPS.From the hardware point of view it looks like a very capable instrument. All thanks to the advances in telecom technology. Most of these high speed ADCs and DACs that we see nowadays in the budget gear has its origins in developments in RF for 3G/4G or core network (fibre optic, DWDM etc) equipment.It's a pity it is above my budget, so I'll have to keep using my Hantek HDG2002B.The only question left is: how is the firmware? My Hantek from hardware point of view is also fairly decent, especially for the price (~$300), but the firmware is absolutely awful

author: EEVblog
author_rank: Unknown
timestamp: October 08, 2015, 12:03:41 am
content: Quote from: Armxnian on October 07, 2015, 11:37:56 pmYes. Explanation in a video uploading now.

author: AF6LJ
author_rank: Unknown
timestamp: October 08, 2015, 12:30:10 am
content: Thanks Dave Great job.

author: Radio Tech
author_rank: Frequent Contributor
timestamp: October 08, 2015, 12:58:16 am
content: Pretty nice built kit for the price.Like to see a performance review.

author: Stephen Durr
author_rank: Contributor
timestamp: October 08, 2015, 12:59:52 am
content: Forgive me if this question has been asked before, but can anyone elaborate on why the q.c. stickers on the back do not instill confidence? Dave mentions this at 1:54 in this video and I noticed the same comment at about 0:53 of the tear-down video for the Siglent 1000X, and I'm pretty sure I've heard similar comments about stickers on other product tear-down videos in the past. So what is it? Are the stickers considered cheesy? Do they make you suspicious of the manufacturer's QC process?Sorry if this is basic but I'm a noob

author: tautech
author_rank: Super Contributor
timestamp: October 08, 2015, 01:22:03 am
content: Quote from: Stephen Durr on October 08, 2015, 12:59:52 amYeah I feel these snipes are just cheap shots too.They show the instrument has been checked against published specs.But what really matters is the Cal certificate which is the official record of Quality Control and proves the instrument meets its design spec. Without a Cal cert as the official record, sure anybody can wack whatever sticker they like on gear and no doubt some do.Let's hope Dave does spends a moment in future vids revealling what equipment DOES NOT come with a Cal cert, that will be more meaningful than mention of a particular "looking" sticker.@ Stephen DurrYou might have noticed Dave did mention the additional Cal label on the SDS1000X series and this label seems like a new addition to the Siglent range.

author: FaultlineAudio
author_rank: Unknown
timestamp: October 08, 2015, 01:25:29 am
content: Great tear down Dave. I'm in the market for a Arb Gen and I had though of buying the Rigol DG4162 until I saw the Siglent in the Oscilloscope review you did earlier.I hope you do a review/comparison video between the two models. The Siglent seems to be a better, higher quality choice than the Rigol.ThanksChris

author: c4757p
author_rank: Super Contributor
timestamp: October 08, 2015, 02:15:36 am
content: Quote from: Stephen Durr on October 08, 2015, 12:59:52 amThey are a style of QC sticker that is well known for being used on cheap crap. It's entirely a subjective comment, but I feel the same way - those stickers immediately make me think of crap products where the only quality control test is "does it fit in the box?". They remind me of a soldering station I bought once that had a sticker on it that said, I shit you not, "QENUINE". The transformer went up in smoke after a couple months, naturally.Siglent are improving in actual, internal quality, but they still have a way to go before the instrumentslook like it. Seriously, I want to peel off the sticker on the front just to hide that MS Office 97 WordArt-looking "True Arb" label! Sure, it's subjective, but looks are more important to make a sale than we engineering-types often want to admit.

author: Armxnian
author_rank: Regular Contributor
timestamp: October 08, 2015, 02:33:55 am
content: I agree that they make the product look cheap. They are also meaningless. Both my Siglent units have the stickers, both of them have rust...

author: SteveLy
author_rank: Regular Contributor
timestamp: October 08, 2015, 02:55:49 am
content: Those QC Passed stickers are seen on the cheapest dodgiest $2-shop items, so indeed they don't instil any confidence

author: Smokey
author_rank: Super Contributor
timestamp: October 08, 2015, 03:19:00 am
content: The whole QC procedure is sticking stickers on. If they stick...QC PASSED!

author: daqq
author_rank: Super Contributor
timestamp: October 08, 2015, 04:52:30 am
content: Hi Dave, thanks for the teardown.The EN2342 is expensive, but all you need for it is a few caps and resistors on the output - it has an integrated coil inside. The weird shape on the bottom is the coil winding. Basically it's the equivalent of the LMZ series from Ti.

author: Aaguilar4
author_rank: Newbie
timestamp: October 08, 2015, 12:24:40 pm
content: Thanks for the teardown Dave. I,ve been a huge fan for at least three years, but this is my first time on the forum.I never undrstood who would want to buy these power modules like Enpirion before. They are very expensive compared with building your own 4A converter, and all they offer really is integrated magnetics (also the reason why the package is so thick).It seemed to me like this was a good idea for prototyping and gettig something out the door quickly. But for serious products built down to a price, doesnt make much sense at all.My guess as to the ground plane is two-fold:1st) thermal dissipation of power loss in the FETs and the inductor2nd) low parasitic inductance of ground connection to the low-side switch in buck converter. In this type of package, the die is flipped, connected directly to the leadframe, which gets rid of bondwires typically found in QFN. These bondwires add parasitic resistance and inductance. in the case of this Enpirion part, large strips of PCB copper connect pretty much directly to the switches inside your die.All the best and thanks for all your videos!Alvaro

author: GNU_Ninja
author_rank: Regular Contributor
timestamp: October 08, 2015, 12:39:31 pm
content: Quote from: SteveLy on October 08, 2015, 02:55:49 amJust had a look at the back of a UNI-T UT58A multimeter that I brought into work to test. Sure enough, there's a gold QC passed sticker on the back. The company that makes those stickers must be coining itMind you, it also says CAT II 1000V rated on the front of the UNI-T. Yeah, right

author: daqq
author_rank: Super Contributor
timestamp: October 08, 2015, 12:56:18 pm
content: QuoteActually, they are quite useful for a lot of reasons:1. Just-add-water philosophy. All you need is a few extra components which you can source from pretty much anyone with very little fuss. Compare it to rolling your own: Source the inductor, source the caps, the main IC, diodes, FETs... Here all of the critical components are given to you.2. Optimized spatially - you'll have to try very hard to outperform things like these modules in terms of power to volume ratios. For a similar construction you'd need more board space and you might still not get the same specs. See thehttp://www.ti.com/ww/en/simple_switcher/qfn-package-modules.html#nanonano series for an extreme of this.3. Optimized performace wise - to get a good DC DC converter, all you need to do these days is slap together a few components that have close-enough specs. To get a really good DC DC converter you have to pick your components for quite some time, test them, poke and prod them, test the whole setup... In these modules someone did it for you. As they did the EMC testing. Also the mechanical design. Essentially, this:http://www.ti.com/lit/ds/symlink/lmz31530.pdfgives you 30 Amps from a package the size of a 30Amp inductor, without any hassle.Yes, at the end of the day you are just saving time. They offer nothing you could not do on your own, eventually, with the right tech (which might get costly). But itcan(depending on the situation)save you time, board space, efficiency.edit: This one's nice as well:http://www.intersil.com/content/dam/Intersil/documents/isl8/isl8273m.pdf

author: EEVblog
author_rank: Unknown
timestamp: October 08, 2015, 01:18:14 pm
content: Quote from: Aaguilar4 on October 08, 2015, 12:24:40 pmWelcome!What this part offers is a guarantee that it's going to work with the Altera FPGA they are using (think obscure power-up current spike issues etc). It's proven, it's no fuss, one less thing the designer has to worry about about. Quite common practice. They obviously aren't shaving every last cent off the BOM cost.

author: Fungus
author_rank: Super Contributor
timestamp: October 08, 2015, 01:38:41 pm
content: Quote from: Stephen Durr on October 08, 2015, 12:59:52 amMaybe a car analogy would help:How would you feel if you bought a new car and it had one of those stickers on the back?

author: Godzil
author_rank: Frequent Contributor
timestamp: October 08, 2015, 02:28:46 pm
content: Quote from: EEVblog on October 08, 2015, 01:18:14 pmYeah but in professional product, price of component doesn't matter right? I mean they try to made the best tool that work well in all conditions, no matter the price!What, why someone tells me that some company doesn't care about quality and just do that for money and try to make the cheapest possible device?

author: Earendil
author_rank: Regular Contributor
timestamp: October 08, 2015, 06:48:54 pm
content: Could someone explain why this instrument only have 20Mhz arbitrary wave output, when its DAC is running at 1230Mhz, please?I feel confused.

author: rf-loop
author_rank: Super Contributor
timestamp: October 08, 2015, 07:28:17 pm
content: Quote from: Earendil on October 08, 2015, 06:48:54 pmVery much simplified for imagine what is going there.What you thing if Arb memory have 5 cycle on sine wave. Then you set Arb frequency 20MHz. What is output frequency. It is 100MHz. Oh but Arb waveform max is 20MHz. Yes, but just One Arb waveform have 5 cycle in this case..20MHz is how fast it can repeat whole Arb memory (it also depends how many Arb memory points waveform have)For thinking. You have 100 memory points long Arb waveform what you have made. Then you set Arb frequency to 10MHz. How fast it need run from point to point in arb memory. What is stepping frequency. 10MHz x 100=1000 MHz

author: ivan747
author_rank: Super Contributor
timestamp: October 08, 2015, 08:26:05 pm
content: Quote from: Stephen Durr on October 08, 2015, 12:59:52 amThis exact model of sticker is often used in some of the cheapest, lowest quality products China has to offer.

author: ivan747
author_rank: Super Contributor
timestamp: October 08, 2015, 08:27:21 pm
content: Quote from: c4757p on October 08, 2015, 02:15:36 amNew signature right there.

author: nixxon
author_rank: Frequent Contributor
timestamp: October 08, 2015, 09:04:49 pm
content: Airflow4:36 into the video, it is commented that the ribbon cables are blocking the vents.Maybe they deliberately block the upper vent holes with the ribbon cables to increase the airflow onto the components which are located at the bottom.Between 3:55 and 3:58 into the video, the instrument was starting to fall down. Let's hope it didn't fall too hard.

author: nowlan
author_rank: Frequent Contributor
timestamp: October 08, 2015, 09:39:41 pm
content: Is the ground cable that was on a spade plug up to code? Thought you needed shake proof washers etc.

author: apis
author_rank: Super Contributor
timestamp: October 08, 2015, 10:38:52 pm
content: "Latest EEVblog Video" on the website is still #804

author: DanielS
author_rank: Frequent Contributor
timestamp: October 08, 2015, 11:21:15 pm
content: Quote from: ivan747 on October 08, 2015, 08:26:05 pmThose cheap stickers, or even cheaper plain paper ones, can also be found in more expensive equipment. Their only purpose is to keep track of which units have passed through QC stations. They do not tell you anything about what the individual stickers stand for. For all you know, the last "QC" sticker you see on the housing could very well be someone checking that all the chassis screws are present and tight.

author: ivan747
author_rank: Super Contributor
timestamp: October 08, 2015, 11:29:44 pm
content: Quote from: rf-loop on October 08, 2015, 07:28:17 pmExactly. If you fill up the memory, it can repeat itself 20 million times per second, but what you have on that memory can have higher frequency components in it.You can also fill only a small part of the memory, say 1/2 of the memory, then it will repeat at 40MHz, if I am not mistaken. Is that right, rf-loop?

author: LapTop006
author_rank: Unknown
timestamp: October 09, 2015, 02:29:19 am
content: Quote from: lukier on October 07, 2015, 11:44:37 pmOrigins yes, but quite old ones. 1g equipment (~1.2g often base rate) entered mass deployment right around 2000 (with carrier core elements of 2.5g OC48 a few years prior), 10g was in mass deployment maybe 2010, and we're just now seeing the wide deployment of 100g equipment (in a 4x25g form) in network cores.The latest DWDM equipment is now doing 400g/wavelength, going to 16, 64 and even higher QAM rates driving 20+ terabit per fibre pair.Certainly some of it is from the mobile world where chips and miniaturization of LTE are starting to offer us really nice platforms for SDR at quite amazingly low prices.

author: rf-loop
author_rank: Super Contributor
timestamp: October 09, 2015, 06:03:34 am
content: Quote from: ivan747 on October 08, 2015, 11:29:44 pmMy quess is: No.I do not know exactly how just this Siglent SDG2000X works in details. I do not have it (yet).I think user can select only max 20MHz repeating frequency for stored arbitrary waveform.It is "True Arb" technology and if it works so that it do not "jump over" memory points lets think.( this is not Siglent or any other named generator. Just basic thinking:If need handle every single Arb memory points in memory and Arb repeating frequency is 20MHz. Hmm... if Arb memory read speed is 100Mpoints/s how many memory points we can read. 20MHz cycle time is 50ns. We can read only 5 memory points in one turn.. (5x10ns=50ns) If we can read arb memory points using 1Gpoints/s then with 20MHz repeating frequency we can read 50 memory points.)I do not know at all what is exactly maximum speed what Siglent SDG2kX can process Arb memory and how it is arranged for amounts of waveform points etc. I hjave understood they use "True Arb" for imply that it do not jump over any single memory points (?)Siglent web side:QuoteThis is one "good to read" paperhttp://www.alliedelec.com/images/Products/mkt/pb/Tektronix/Pdf/understanding_signalgeneration.pdfI hope Siglent do better material for show exactly how it works and what are limits exactly. Whole principle exactly with all information with numbers how it works and how it do not work. It is very extremely different what is example in SDG800, 1000 and 5000 generators.Example with every SDG1000 can produce 50MHz sine out using Arb, There Arb max repeating frequency is 5MHz. There you can do 10 cycle sine to arb memory and run it using 5MHz and out come 50MHz. But if there is short details in arb memory it may (randomly!) jump over it because this model have fixed arb memory lenght and fixed clock. Missing details is one disadvantage what user need know. When it have 125MSa/s it mean it have 8ns step interval. It have 16kpoint Arb memory. If handle every Arb memory points without missing points then how much time it need. 8ns x16000 = 128000ns = 128us. Whole Arb memory every single points can then handle only if repeating frequency is under 7.8 kHz ! If go over this Arb frequency it need start skip over memory points and due to fixed clock in every turn different memory points are skipped. (depending frequency. There can also find special frequencies where skipping and waveform iare "in synch". This is disadvantage in all fixed clock fixed memory lenght "simple principle Arb generators" independent of manufacturer name.)SDG2000X is very very differentand it have more advanced principle. It have variable Arb memory lenght and variable Arb memory "stepping" speed and then this Arb repeating frequency what have limit value max 20MHz. And this is not only in Siglent, it is and have been long time, in many bit more advanced generators. But perhaps with different details combination.All is adjusted so that there is "No detail in your waveforms will be lost." And it is perhaps much much more important than maximum frequency what it can produce.It need think for what we use and need arbitrary waveform function.But, as told, Siglent need write better specification so that we can read exactly what it do and what it do nnot do. How it works, exactly. This is important so that buyer do not disappoint. If you promise gold and buyer find brass all are disappointed and angry. But you have his money and you are still happy, you win. If you do it fast enough you can win many.... But, try repeat it... no way. On the chinese street corners this happends thousends of times every day and you can change street corner and repeat, you can change city, and repeat... but here, international markets you can not run to ther corner, other city... so, this is different.If you promise brass and buyer find he also get brass he is satisfied. If you promise gold and buyer get gold, agen he is satisfied. In both cases you can continue and continue win. If one is not satisfied he tell it to thousends, ten thousends, to whope world of peoples. You have just one shot... If one is satisfied perhaps he do not talk anything.. Good enough deep and open information about product, it is ONLY way to do and continue. Please learn how HP build they brand... start reading example HP journals from history. How much they tell and explain lot of things.. well explained some new equipment working principles including also very deep details. Why they do not afraid copycats. They show all schematics, they show even part of design calculations and theories and things how they have developed something. Why they do not afraid copycats.Everyone can copy schematic, everyone can solder and do printed circuits, all can do.What can not copy? Lets assume that price is still limit. Answer is: Quality. This can not copy (so that price is cheap enough for copycat business)Who is first chinese company what really realise this and do it. I'm waiting.

author: sergey
author_rank: Regular Contributor
timestamp: October 10, 2015, 07:04:37 am
content: Dave, very nice video, thanks!Got a question to the audience tho. It seems 10MHz reference input is fed to the main board via ribbon cable. Is it gonna to cause some parasitic leakage and hence have negative effect on the instrument stability?

author: f4eru
author_rank: Super Contributor
timestamp: October 10, 2015, 01:02:26 pm
content: Quote from: Earendil on October 08, 2015, 06:48:54 pmBecause you need a lot higher a sample frequency to render your waveforms properly.Also, it's uncommon to use an arb at higher frequencies. Usually you need an RF generator (extremely clean sine + modulation only) on the higher bands

author: Dr. Frank
author_rank: Super Contributor
timestamp: October 10, 2015, 07:00:05 pm
content: Thanks Dave, for that interesting teardown video.Well explained, and just the right length.These Q.A. / Q.C. stickers on the back.. in contrast to that, many solder joints , especially at resistors, (@15:00min) they look really awful, they wouldn't have passed the AOI in our assembly plant.The solder meniscus does not look smooth and clean, more looking irregular, and not fully wetting the surfaces, like manually soldered.Was it an inhomogeneous solder profile, or too low solder temperature?That will for sure become a severe quality problem after a few years of operation.Frank

author: analogNewbie
author_rank: Regular Contributor
timestamp: October 13, 2015, 03:39:45 pm
content: The firmware from siglent website for SDG2000X has high entropy. It seems that they encrypted the firmware by some algorithm.If someone wants to check out the frequency unlocking code, one should buy one and dump the flash. I think from 40MHz to 120MHz the only difference is inside the software. Hope they dont change the output opamp to reduce the cost.

author: billfernandez
author_rank: Regular Contributor
timestamp: October 14, 2015, 05:16:49 am
content: I've been looking through the user manual and datasheet and thought I 'd share a few notes about the SDF2000X series:MAXIMUM OUTPUT FREQUENCIES:sinewave up to 120MHz.squarewave up to 25MHz.ramp ( incl. triangle) up to 1MHz.pulse up to 25MHz.Noise up to 120MHz bandwidth.Arbitrary waveforms up to 20MHz.(The specs don't say whether the non-sine max frequencies are lower than shown above if it's not a 120MHz model.)MISC NOTES:o Modulation input 50KHz max.o Sync output = 500nS pulse. When the frequency of the waveform is greater than 1MHz, there is no sync signal output.o The base unit can be upgraded to higher frequencies by entering a license code.o The manual says "SDG2000X supports 40MHz, 80MHz and 120 MHz bandwidth for now." (what does "for now" mean?)o Zout = 50 Ohms. If you want the Vout readout to be correct, you must tell the unit the impedance of your load (over a 50 Ohm to 100K Ohm range).o The 200MHz frequency counter seems to resolve to 1Hz, and is independent of the two signal generator outputs. So all three can be used at the same time.o Digital values are drawn from ARB memory at a basic clock rate of 300MHz. These values are fed to an interpolator that runs at four times that rate (1.2GHz) and which generates interpolated values between the old and new value. Thus for each "real" value drawn out of ARB memory four values are presented (in turn) to the DAC, resulting in greater Spurious-Free Dynamic Range (SFDR).

author: tautech
author_rank: Super Contributor
timestamp: October 14, 2015, 06:23:28 am
content: Quote from: billfernandez on October 14, 2015, 05:16:49 amWelcome to the forumJust pointing out your typo ^Should be SDG

author: TheSpruceMoose
author_rank: Newbie
timestamp: December 05, 2015, 01:46:22 pm
content: Quote from: sergey on October 10, 2015, 07:04:37 amI actually had the same reaction at first when I saw that ribbon cable!It seems like you could have some capacitive loss, but if your reference signal doesn't have any content at other frequencies, I think it wouldn't affect the overall quality of the signal (i.e., an RC filter at one frequency is just an attenuator)... At 10 MHz, the wavelength is ~3m, and I think that you don't really have to worry about reflections or other weird high-speed stuff until the line is longer than ~10% of the wavelength (30cm (1ft) here). Maybe that's different when it's a really high-quality signal? I have really, really limited knowledge and experience, so I could be exceptionally wrong :/The frequency counter input is on the same ribbon cable, and it can supposedly count up to 200 MHz, so I *really* wonder how much that would be affected...