Which SMU -- Keithley 2450, Keysight B2901B, R&S NGU401? - Page 1
Forum section: electronics / testgear

author: colorado.rob
author_rank: Frequent Contributor
timestamp: November 30, 2021, 03:41:57 am
content: I'm in the market for an SMU. I will primarily be using it for battery-powered system testing, but I have some additional needs that make an SMU a worth-while purchase. One key requirement is that it be network accessible (LXI), which leaves a lot of older equipment out of the running. Keithley seems to be the go-to choice for an SMU. R&S is new to the space, but certainly seems worth considering. I've not heard much about the B2900 series from Keysight other than a disparaging remark about the UI. The low-end models are all close to the same price USD5000-6000.Having a dedicated application for battery simulation would be nice but is not a necessity since I am adept at lab automation.Looking to the experts here who have experience with these units to share their thoughts. Are there SMUs not on the list worth considering? Are there any features that stand out as unique to any of these models?

author: Someone
author_rank: Super Contributor
timestamp: November 30, 2021, 04:34:14 am
content: Quote from: colorado.rob on November 30, 2021, 03:41:57 amCompletely fair assessment of those models, they're descended/derived from semiconductor testing equipment and are very very fiddly to use manually. Much of the automation is built in for sweeps/sequences/delays/triggers etc so they can measure as fast as possible. But again, pain in the neck to setup as they follow semiconductor test methodologies/patterns with its own lingo and not a more general purpose UI. Supplied "Free" software to use them is pretty rudimental and doesn't really show off their capabilities. If you're ok learning the command set and doing it all over LXI/VISA none of those should not be issues for you.The associated/derived Agilent/Keysight models are the SMUs B2901/B2902/B2910/B2911/B2912 and also power supplies B2961/B2962. Meters B2981/B2983/B2985/B2987 are similar UI/casing but different internals:https://www.eevblog.com/forum/metrology/keysight-b2980a-series-electrometerpicoammeter-teardown/That said if you're not needing high speed and/or extremely low ranges, a modern power supply might do for your application. Some of the R&S models sit somewhere between the two.

author: Joel_Dunsmore
author_rank: Regular Contributor
timestamp: November 30, 2021, 04:38:13 am
content: I've personally used the B2912 and one nice feature is the ability to do triggered high-speed measurements and then read the data out after you are done triggering. we use this feature when when use the B2912 along with the PNA-X to sweep a drive voltage (often gate on a GaN device) and measure drain while measuring the RF gain properties. We can get nicely traces of Gate voltage, drain voltage and current, RF input and output. We use hardware triggering to get speed and then count triggers to get the right number of points and read out the data arrays at the end. i think we can get as fast as 50 microseconds a point on the B2912.

author: Xandinator
author_rank: Contributor
timestamp: February 11, 2022, 01:26:52 am
content: In case you haven't pulled the trigger on one of those yet: The B2900 series' UI takes a little to get used to (still I prefer the B2987's UI/ergonomics over the 6517B, although I don't have any in-depth experience with the latter), so I could not put up with it being the primary workhorse. In contrast to this, Keithley and R&S really nailed it with their graphical (touch) UIs – just a pleasure to use. I wonder why nobody has been considering the NGM202 as an option so far, which I would deem ideal for the battery testing part (lots of power under the hood, 2 channels you trade off 2 quadrants for, could have added more ranges, triggering is OK once you have wrapped your head around it, battery simulator). If 4 quadrant is a must, I would probably go with Keithley though, especially if you already have their DMM/DAQ...

author: luudee
author_rank: Frequent Contributor
timestamp: March 11, 2023, 09:54:19 am
content: I realize this thread is about a year old ... but ...Has anybody looked at the SMU from ITECH (IT2800)?https://www.itechate.com/en/product/SMU/IT2800.htmlThis is a "Graphical SMU" whatever that means, lolAppears to me the R&S unit is missing a ton of features ....Thnks !luudee

author: eplpwr
author_rank: Regular Contributor
timestamp: March 11, 2023, 10:32:49 am
content: Quote from: luudee on March 11, 2023, 09:54:19 amI can't find any pricing for these, using google. Seems to be three models: IT2801 1kV version, IT2805/06 200V and -06 with some pulse capability.Specs very close to Keithley/Keysight except 20W max power.

author: luudee
author_rank: Frequent Contributor
timestamp: March 11, 2023, 04:47:22 pm
content: Quote from: eplpwr on March 11, 2023, 10:32:49 amLooks like Keithley is also 20W, but I couldn't find a spec'ed max power for the Keysight ...Do you know what it is ?So hard to decide what unit I should get. I think 20W will be sufficient for the typical work I do.Many Thanks for your feedback !luudee

author: jc101
author_rank: Frequent Contributor
timestamp: March 11, 2023, 05:49:11 pm
content: Have you considered the AimTTI SMU4000 series?https://www.aimtti.com/product-category/source-measure-units

author: zrq
author_rank: Frequent Contributor
timestamp: March 11, 2023, 06:32:55 pm
content: How they achieved 100fA resolution without even shielded terminals....?

author: Hydron
author_rank: Super Contributor
timestamp: March 11, 2023, 10:52:31 pm
content: Looks like there is a guard terminal on the rear (and sense+ doubles as guard on the front panel). Keysight and Keithley use similar banana connectors on their bench SMUs (KS with an explicit guard on the front panel, Keithley with it just on the rear panel, with either triax or "phoenix" style connectors).In terms of personal experience, I added a connection box to my Keithley 236 (now upgraded to a 237) which uses safety banana sockets for ease of use - they seem to work just fine and don't leak (the design of a shrouded socket inherently keeps the creepage distance of the contacts very long), though I also put a triax connector on it in parallel for when I use external test enclosures. Makes the unit a heck of a lot more useful as an everyday instrument not needing to use triax for everything. See here for pics if interested:https://imgur.com/a/UCuxtMU

author: luudee
author_rank: Frequent Contributor
timestamp: March 12, 2023, 07:35:45 am
content: Quote from: jc101 on March 11, 2023, 05:49:11 pmThank you JC (?), this SMU looks like a really good deal, and the PC software looks nice as well. Definitely the cheapest one among them all ...Are there any shortcoming compared to the other brands? I did look through the datasheets, but did not see anything ....Many Thanks !luudee

author: jc101
author_rank: Frequent Contributor
timestamp: March 12, 2023, 09:45:16 am
content: Quote from: luudee on March 12, 2023, 07:35:45 amI needed an SMU for a project a couple of years ago and rented a Keithley 2450 for a few months instead. The purchase costs were too high at the time. Thinking about a project that may come my way later in the year I have been thinking about getting an SMU again. This one popped up in my searches, I think it came out last year. I have quite limited space, so a bonus for me is the small size.

author: luudee
author_rank: Frequent Contributor
timestamp: March 15, 2023, 11:38:24 am
content: So, this is my final list of SMUs. Did I miss any?1. ITECH IT2806 $7,000 USD (approx)https://www.itechate.com/en/product/source-measure-units-smu/IT2800.html2. Keysight B2901B $9,394 USDhttps://www.keysight.com/us/en/product/B2901B/precision-smu-1ch-100fa-resolution-210v-3a-dc-10-5a-pulse.html3. Keithley/Tetronics 2450 $9,800 USD (approx) (38-42 week lead time)https://www.tek.com/en/datasheet/smu-2400-graphical-sourcemeter/model-2450-touchscreen-source-measure-unit-smu-instrument-4. Keithley/Tetronics 2461 $11,200 USD (32 week lead time)https://www.tek.com/en/datasheet/2461-graphical-source-measure-unit5. AimTTI SMU4001 $3,999 USDhttps://www.aimtti.com/product-category/source-measure-units/aim-smu40006. R&S NGU401 $8,160 USDhttps://www.rohde-schwarz.com/us/products/test-and-measurement/dc-power-supplies/rs-ngu-source-measure-units_63493-1005128.html7. GW Instek GSM-20H10 $5,060 USDhttps://www.gwinstek.com/en-global/products/detail/GSM-20H10>>> NOTE: Prices listed here may be inaccurate. If not listed on their website, I googled the unit model number and looked for a price that way. <<<They are mostly equivalent from a functional standpoint. Most will do 20V/3A/20W, some will go up to 200V, and accuracy variations are there as well ....I am thinking of the AimTTI unit for now ... but am not in a hurry .... if anybody has more suggestions I am open to them.Cheers,luudee

author: ch_scr
author_rank: Frequent Contributor
timestamp: March 15, 2023, 01:14:54 pm
content: For completion, there is also the Keithley 2600 line of SMU's. Not a graphical UI, but a VFD based one. It's quite usable as a bench unit.All the I/O, including LAN, is on the back. I've made 3d printed "ears" for mine to have breakouts on the front, but it's a non-standard width then.Have a look herefor that and other peoples solutions.These are heavily used in semiconductor manufacturing and available with all triax connectors. Single and dual channel units are available in the same volume. There is areallynicepython libraryon github, which works very well and allows to basically carbon-copy the commands from the manual. It does all the heavy lifting when doing pulsed-mode measurements, where all the data is on the device and is only transferred over after the measurement.Downside: they get quite warm even doing nothing, and the fan (that will be running all the time) can get annoying in a quiet lab. When working as a load, these and most similar SMU a) get really loud (some say they sound like a starting jet...) and b) when used as an electronic load, there is quite a caveat:Usually, to test your supply, you would set a current draw and a compliance voltage limit - as long as your supply can source that, all is as expected - but as soon as the supply goes into shutdown (or can for any other reason not supply the set current draw) most SMU will switch to "the opposite quadrant" and put a negative voltage (up to the compliance limit) on the output of your power supply, trying to get the current to flow! On most units this behavior can not be influenced, certainly not on the K2600, so buyer beware. You can of course put a diode in series, but maybe rather check if there is a unit which can be told to behave in a more desirable way, if you want to do this.Edit: There is also the Yokogawa GS200, but only up to 30V/200mA.

author: pdenisowski
author_rank: Super Contributor
timestamp: March 15, 2023, 02:04:55 pm
content: If you're interested in learning about the NGU, I made a video that goes through its functions and how they are configured.

author: HighVoltage
author_rank: Super Contributor
timestamp: March 15, 2023, 02:10:25 pm
content: I used to have a Keysight SMU 2987A and did not like it too much, mainly because of the UI. So I sold the Keysight SMU again and instead got the Keithley 2450 and 2460.These are very good instruments, surpassing the Keysight SMU in all practical aspects.

author: luudee
author_rank: Frequent Contributor
timestamp: March 15, 2023, 04:18:14 pm
content: Quote from: pdenisowski on March 15, 2023, 02:04:55 pmThank you, Paul! Appreciate the educational videos!Now, if you can do magic about lead times, I'd be very grateful!!!!Cheers,rudi

author: pdenisowski
author_rank: Super Contributor
timestamp: March 15, 2023, 08:28:40 pm
content: Quote from: luudee on March 15, 2023, 04:18:14 pmThanks! And I'll see what I can do on lead times

author: mawyatt
author_rank: Super Contributor
timestamp: March 16, 2023, 12:47:35 am
content: Another potential candidate.https://www.gwinstek.com/en-global/products/detail/GSM-20H10https://www.valuetronics.com/product/gsm-20h10-instek-sourcemeter-new?gclid=Cj0KCQjw2cWgBhDYARIsALggUhqkt7OqHJVJgzWxO1YscdCuClvaYLLD7yFYZn1PK3AGztOktqtr4e8aAvrgEALw_wcBBest,

author: luudee
author_rank: Frequent Contributor
timestamp: March 16, 2023, 03:34:46 am
content: Quote from: mawyatt on March 16, 2023, 12:47:35 amThank you Mike ! Much appreciated :-)I added the unit to the list ...luudee

author: Xandinator
author_rank: Contributor
timestamp: March 21, 2023, 01:45:11 am
content: IMO the 2450 and 2987 are completely different instruments. Sure the UI of the 2450 would be nice on the 2987 but when using one I actually never thought of substituting it by the other and vice versa.

author: nomead
author_rank: Contributor
timestamp: March 21, 2023, 04:48:33 pm
content: Quote from: luudee on March 15, 2023, 04:18:14 pmIf long lead time isn't problem enough and you want also issue with general availability there is also ADCMT (ex Advantest)https://www.adcmt.com/en/products/vig

author: colorado.rob
author_rank: Frequent Contributor
timestamp: March 21, 2023, 05:01:57 pm
content: Looks like Yokogawa has a few SMUs as well :https://www.ttid.co.uk/source-measure-units

author: TheSteve
author_rank: Unknown
timestamp: March 21, 2023, 10:24:25 pm
content: Just to add the Keithley 2600 series does not have LAN. You need the 2600A or 2600B series for LAN.I also have an as new Keysight B2901A if someone is looking for one that I may part with.

author: colorado.rob
author_rank: Frequent Contributor
timestamp: November 15, 2023, 02:51:57 am
content: I started this thread quite a while ago. I finally placed an order for an R&S NGU401.Newark is selling these at a 50% discount (~4200USD) right now:https://www.newark.com/rohde-schwarz/ngu401com/source-meter-unit-20v-60w/dp/13AJ3128

author: TheSteve
author_rank: Unknown
timestamp: November 15, 2023, 07:16:15 am
content: Looks decent enough - only 20 volts is a bit of a bummer.

author: colorado.rob
author_rank: Frequent Contributor
timestamp: November 17, 2023, 03:31:52 pm
content: LOL -- that price did not last long.

author: mawyatt
author_rank: Super Contributor
timestamp: December 27, 2023, 04:39:58 pm
content: @ colorado.robAwhile back we inquired at Newark about the NGU401 and they were out of stock, and were going to be back in stock 12-18-23 and would notify us. Newark never notified us, and now they are back at full price and still no stock!! We've pinged Newark about this!!Have you been doing much with the NGU401?A few questions about the NGU401, is/are there available software for doing things like simple low resistance measurements, Semiconductor Curve Tracing, and Gummel Plots? Is this an extra cost, or part of the NGU401 support?Best,

author: colorado.rob
author_rank: Frequent Contributor
timestamp: December 27, 2023, 04:56:26 pm
content: I received mine a few days before Christmas. I have not unboxed it yet.I write custom applications in Python using PyVISA. Vendor software is not something I typically care about.There are a number of applications available here:https://www.rohde-schwarz.com/us/application/ngu/There is a curve tracer application for 2-pole devices.