hybridfree/eevblog-posts huggingface dataset:
Adjustable Voltage Regulator with Digital Interface???......... - Page 1
Forum section: electronics / projects

author: Smokey
author_rank: Super Contributor
timestamp: October 04, 2016, 07:02:03 pm
content: I'm looking for a switching voltage regulator with an adjustable output that I can control digitally. Something like I2C is perfect. SPI is acceptable. 1Wire if I had to. A DAC controlling a regulator with a feedback pin is an absolute last resort.Specs:>15V input voltageUp to 5.5V output voltage>=500mA output currentCheap as possible.No BGA if possible.Hits?

author: ajb
author_rank: Super Contributor
timestamp: October 04, 2016, 07:10:31 pm
content: Have you looked at PMICs meant to be used with microprocessors (core voltage regs, etc)? That's where you're most likely to find a digital interface, but not sure if you'll hit your output voltage spec in that application space.

author: jitter
author_rank: Frequent Contributor
timestamp: October 04, 2016, 07:33:36 pm
content: Yeah, something similar to TI'sTPS65233.

author: Smokey
author_rank: Super Contributor
timestamp: October 04, 2016, 08:51:29 pm
content: That TPS65233 looks killer, and not bad at $2.74USD in 1s...But the output voltage is only 13.1V to 13.7V or 18.2V to 19V. Can't get it down to around 5V.

author: Euphyllia
author_rank: Newbie
timestamp: October 04, 2016, 09:01:14 pm
content: Quote from: Smokey on October 04, 2016, 07:02:03 pmWhy the kibosh on this? Seems like a low-passed PWM output summed into the feedback pin would work fine unless you have some other requirements.

author: technix
author_rank: Super Contributor
timestamp: October 07, 2016, 05:31:37 am
content: You can also cook up your own regulator by controlling a Buck converter using a microcontroller with PWM output and ADC input, preferrably using a few spare PWM and ADC pins on your main application processor to reduce part count.For the simplest design you can use the traditional Buck circuit with a PMOS, a Schottky diode and an L/C filter. If your MCU supports complimentary PWM with dead-zone configuration you can use some advanced control mechanisms like synchronous NMOS buck converter (using two NMOS, a gate driver chip like IR2110 and a L/C filter).

author: tszaboo
author_rank: Super Contributor
timestamp: October 07, 2016, 08:56:59 am
content: So something, like LTC3883?The hard part, your requirement is too small current. Most of these power supplies with I2C interface are for high power/current, with discrete FETs and stuff. I would take a look at Linear technology. Also, On semi is huge in the computing business for core voltage regulators.

author: technix
author_rank: Super Contributor
timestamp: October 07, 2016, 02:12:00 pm
content: At least to me, for small-scale projects, I often use ATtiny85 as PMIC. Those small microcontrollers are often cheaper than those dedicated digital PMICs (usually requires external MOSFETs anyway) and have a 64MHz timer with bipolar PWM mode which allows me to use smaller inductors and synchronous rectifying if I find the need to do so.
Adjusting Signal Amplitude and gain (Without pots in the signal path?) - Page 1
Forum section: electronics / projects

author: Rerouter
author_rank: Super Contributor
timestamp: June 20, 2016, 11:56:06 am
content: Currently in the midst of creating a little DDS function generator, and could use some input on how best to approach adding offsets and adjusting gain, as the frequencies are a fair bit higher than audio, I felt potentiomers are ruled out.What i would like is to be be able to control the output offset, over the output range and be able to control the output amplitude from 0.2 - 23V p-p, however I'm also aiming for a cheaper solution (1-$10 is good),At the moment i am fine with either digital or analog control,The source is 0.02Hz - 3 MHz (DDS), giving out sine or square, (Lets say up to 40Mhz components)The output of the DDS is 0.6V p-pAttached is the circuit i am currently using to amplify the output, FDAC is the filtered output of the DDS, and FOUT is the output to the external world.

author: seriouscoinage
author_rank: Contributor
timestamp: June 20, 2016, 12:01:22 pm
content: I used an ordinary 1Kohm potentiometer mounted on the DDS PCB to control amplitude for my 10MHz DDS signal generator, and it didn't seem to cause any problems/bandwidth limitations. I think using long wires to the pot or pots with high resistance values might cause bandwidth issues, but I think a pot should be fine for 3MHz. A variable gain amplifier could be an option if you didn't want to use a pot, and because it can add gain, you might be able to leave out another amplifier elsewhere in your circuit.

author: Rerouter
author_rank: Super Contributor
timestamp: June 20, 2016, 12:22:25 pm
content: Where you attenuating the input signal, in the gain path, or on the output?

author: seriouscoinage
author_rank: Contributor
timestamp: June 20, 2016, 12:36:23 pm
content: I attenuated it in the gain path. I've attached a diagram of the circuit I used in my DDS. The first op-amp provides gain, a 220ohm termination for the DDS filter, and DC offset control. I didn't want adjustable offset, so I just connected it to a trimpot and a voltage reference to null out the DDS output offset. If you want offset control, you can just use a pot on the front panel here instead. The first op-amp drives the 1K pot, and the second op-amp buffers the pot signal, adds more gain, and drives the output. This runs off +/-5V rails and gives 6-7Vpp out.
Adjusting speed of quartz clock without adjustment nob? - Page 1
Forum section: electronics / projects

author: Axk
author_rank: Regular Contributor
timestamp: December 01, 2021, 08:08:49 pm
content: This is in continuation of this question:https://www.eevblog.com/forum/projects/measuring-clock-quartz-frequency-accurately/I've one quartz clock that has a dedicated adjustment trimmer pot (suppose it's a cap, but not sure) and I adjusted it comparing the 32.768 signal of the clock to a references on a scope and it's now pretty accurate (off by 1 minute per year)Now in my other (wall) clock there's no adjustment, it's just a chip on board (epoxy blob) connected to the magnetic coil, a crystal and the battery.So I wonder1 - How do I measure the crystal without disturbing the frequency (the other clock has a buffered output, so it's not an issue)2 - If it's possible to retrofit a pot to adjust the frequency somehow (e.g. a trimmer cap across the crystal, or between the crystal and the chip or something like that)

author: bob91343
author_rank: Super Contributor
timestamp: December 01, 2021, 09:23:27 pm
content: You can lower the frequency slightly by a parallel capacitor/trimmer. However, near all those 32kHz crystals have an undesirable temperature coefficient such that critical adjustment of frequency is a waste of time.A real world example is the case of my two clock radios, cheap items but amazingly accurate. One has a green LED display and the other has a red one. With the red one sitting on my nightstand and the green one on top of it, the red one runs faster than the green one at about one second a day. With the green on the bottom, they are almost at the same speed, and don't change much at all from day to day.The slight temperature difference, with the lower one warming the upper one, is enough to change the frequencies by that much.

author: xavier60
author_rank: Super Contributor
timestamp: December 01, 2021, 10:11:21 pm
content: If the clock is running fast, which they usually are, I put some extra capacitance across the crystal formed from 2 pieces of thin enameled copper wire tightly twisted together, about 2 cm from memory.The idea is to first cause the clock to run too slow then gradually decrease the capacitance by untwisting and sometimes cutting off the wires at the free end.I'm able to quickly check the speed by comparing the stepper motor drive pulses to the Pulse-per-second signal from a GPS module.Solder flux residue can cause problems.

author: magic
author_rank: Super Contributor
timestamp: December 02, 2021, 08:38:26 am
content: I have described one solution that worked for me in the old thread.If your clock IC is junk enough the trick may work again
ADM7150 LFCSP footprint - Page 1
Forum section: electronics / projects

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: January 24, 2020, 12:11:31 am
content: Hello all,I was trying to get a footprint for the ADM7150 in the LFCSP package. The data sheet does not provide a suggested layout, and when using Ultralibrarian with the .BXL files from the ADI website, it's clearly the wrong package (it measures 2x2 mm, instead of the 3x3 mm from the data sheet). I'm not well-versed with creating footprints from scratch, so if anyone has a suitable layout for this package please let me know.

author: nardev
author_rank: Unknown
timestamp: January 24, 2020, 01:05:47 am
content: I don't think i can help but what i do in such a situation, i just make a measuring, draw it, print on a paper 1:1 ratio and try to fit in.You will definitely have to make prototype or a two for the device so, you will have opportunity to tune it up.Btw. i usually use Eagle CAD. Just a few days i created several specific pads for a modules for which i have no datasheet.
ADMIN - Cannot reply to just one post of mine...? - Page 1
Forum section: electronics / projects

author: ricko_uk
author_rank: Super Contributor
timestamp: August 01, 2024, 03:28:55 pm
content: Hi Admin (or anybody else who might be able to help)...I tried to comment to this post of mine several times:https://www.eevblog.com/forum/projects/lowest-emissions-electric-motor/But every time I press post nothing happen and the long reply I typed just disappeared.I initially thought it was because I was using my old mobile which had in the past some browser issues. But today I tried again and after typing a long reply, I pressed Post and there is no sign of my post...Why is that? What happened?Thank you as always
ADP1048 current sense Boost PFC? - Page 1
Forum section: electronics / projects

author: AcHmed99
author_rank: Contributor
timestamp: November 21, 2013, 12:27:38 pm
content: I’m trying out theADP1048maybe I’m having a brain fart it’s early here but does this Over Current Protection make sense to anyone? The schematic on the left is fine typical return lead sensing. I don’t really want to sense that current (for pulse by pulse OCP) as it’s the full input current. This is an interleaved BOOST PFC (two phase 180 degrees out of phase) so I want to sense the peak current through each inductor that means measuring from the source through Rsense as depicted in the schematic on the right.How can a voltage develop over the resistor in the fet source if it is bypassed to ground as shown in the schematic on the right?

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 21, 2013, 03:08:47 pm
content: The schematic was drawn incorrectly.
ADP1850 master slave configuration - Page 1
Forum section: electronics / projects

author: anishkgt
author_rank: Frequent Contributor
timestamp: August 12, 2020, 11:05:54 am
content: I am trying to workout the values of modulator Gain and effective fsw on page 22 of the ADP1850(https://www.analog.com/media/en/technical-documentation/data-sheets/ADP1850.pdf). I know its something to do with the calculations mentioned on page 21 which i have but completed but not sure what they are referenced to in page 22.To pair as master and slave these values needs to be doubled but not sure if each would need to be doubled which i think is.So far i haveGm = 500uSRcomp = 40mOhmCcomp = 857ufCc2 = 50uf Randomly picked something between 42uf and 85uf (based on calculations of Rcomp and Ccomp) since that was what was mentioned in the datasheet.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: August 18, 2020, 03:02:08 am
content: Hi,I have not checked the calculation but these numbers that you have:Rcomp = 40mOhmCcomp = 857ufCc2 = 50ufAre off by 10E6Rcomp = 40kCcomp = 820pFand Cc2 = 50pFare more typical values.I suggest you try and calculate the values for the demo board application. You should get pretty close.Jay_Diddy_B
adressable leds - Page 1
Forum section: electronics / projects

author: 4LEKS1
author_rank: Newbie
timestamp: January 29, 2021, 12:51:57 pm
content: Hey! I'm working on project that uses around 200 SK6812 RGBWW leds. The boards are custom is shape, and because the design as overhead lightning I'm running around 24V to each light. So I made custom stepdowm powersupply to handle the conversion to 5V. I used ti's webench powerdesigner page to help me to get right configuration for the voltage controller that I'm using. The controller is LM25145RGYT and the schematics and picture are in the attachments below.(the R4 is actually 20K ohms for setting the frequency to around 500khz) So the output is 5.02V and it keeps it there even when draving 12A with resistive load. but as soon as I drive the leds with it, after just 1A the controller goes crazy, with the frequency bouning here and there, and the voltage getting spikes between 3V and 9V with destructive impacts on the leds. the leds all have 100nF caps close to them, and the "branches" have 8x 4.7uF capasitors on them. So I'm assuming that the leds are generating so much noice, that it messes up with the feedback. what should I do to midigate this problem?-Aleksi

author: Refrigerator
author_rank: Super Contributor
timestamp: January 29, 2021, 04:57:09 pm
content: Maybe try pulling SYNCIN low.QuoteAlso SMPS's don't like big remote capacitances and can go a little unstable.QuoteI don't see anything obviously bad with the schematic. Perhaps there could be a problem with your PCB design?

author: Refrigerator
author_rank: Super Contributor
timestamp: January 29, 2021, 04:59:52 pm
content: Also there's no need to connect PGOOD to anything, it's an open drain output. You use it to indicate to some other device that the power is good.Quote

author: Smokey
author_rank: Super Contributor
timestamp: July 24, 2023, 10:22:31 pm
content: Did you ever sort this out?
ADS1248 - surprising noise versus Vin graph - Page 1
Forum section: electronics / projects

author: splin
author_rank: Frequent Contributor
timestamp: February 17, 2019, 07:34:17 pm
content: I just came across this graph in the ADS1246/7/8 datasheet (24 bit SD ADC) which rather surprised me:Noise v input level graphs aren't especially common in ADC datasheets, but I've never seen one that looks quite like this!The noise level varies dramatically with Vin, between 50nV and 270nV. Typically I would have expected the noise to be relatively flat v Vin, perhaps rising towards the maximum i/p levels where the reference voltage noise starts to become a bigger percentage of the total. (I've seen one where the noise actually reduces at the maximum input, suggesting the reference noise is negligable compared to ADC noise).Unfortunately there is nothing in the datasheet referencing this graph or how the measurements were taken, other than Vdd and PGA gain shown on the graph itself. In particular it doesn't say if the internal, or an external reference was used and perhaps more importantly how long the noise was measured for at each input level - assuming it was done discretely rather than using an analogue sweep (with unspecified noise bandwidth).So would you be happy if you'd selected this ADC on the basis of the 70nV rms noise stated in the noise performance table, not having spotted this graph? Note that the noise performance tables published in pretty much all ADC datasheets are with the input shorted (ie. 0V), and there is no reason to doubt the 70nV figure, but given the unusual wild variation with i/p level shouldn't that have been clearly stated somewhere - eg. by referencing this figure 9 as well as the noise tables in the noise specs?Is this noise characteristic peculiar to this particular ADC (I hope so) or might there be other, similar third-order (or higher) sigma-delta ADCs with similar, noise characteristics but unspecified in the datasheet?Is the graph simply wrong? It's not uncommon to have nonsense graphs in datasheets.

author: Kleinstein
author_rank: Super Contributor
timestamp: February 17, 2019, 08:35:07 pm
content: The curve looks like it comes from a measurement of a single sample. We don't know how the measurement is done. So there could be some uncertainty from the measurement. So I am also not so sure one can take the curve for accurate in every detail. Even if reproducible for the given unit, chances are a different unit would behave different.Sigma delta ADCs are known to have some odd behavior at some voltage levels. This is known as idle tones and can lead to extra noise at some constant voltage levels. So chances are a odd looking curve for the noise is not that unusual for SD ADCs. The details of the higher grade SD ADCs are different and partially well kept secrets and much of this about avoiding the idle tones. With many different solutions the different ADCs may behave quite different.AFAIK idle tones are a problem only for constant input levels. So in some applications it may not matter.
ADS1256: ADS1256 ADC Circuit Design Review - 0.1-20 Hz Signal Sampling at 100 SP - Page 1
Forum section: electronics / projects

author: hsynylcn
author_rank: Contributor
timestamp: April 13, 2025, 06:06:01 pm
content: I designed a circuit using the ADS1256 24-bit ADC, using NE5532 op-amps for signal conditioning and an LM1117MP voltage regulator. I will add the filtering circuit later. Could you please review this schematic and provide feedback on possible issues or improvements? The data I will be converting is between 0.1-20 Hz and I will be sampling at 100 samples per second.

author: Kleinstein
author_rank: Super Contributor
timestamp: April 13, 2025, 08:16:53 pm
content: The AD584 likely does not want a capacitor directly on the output. If one needs some filtering, add a series resistor (e.g. 100 ohm or more).The NE5532 is an odd choice for the reference buffer. It is not very accurate and quite high power. It also need a rather high supply and this can be an issue. Ideally the ref. buffer would be powered from the same supply (e.g. 0 and 3.3 V). This way the ref. voltage can not go higher than the ADC supply and damage the ADC.The ADC may want a capacitor at the Ref. input. So the amplifier should be tolerant to capacitance at the output. The chip seems to have the option to use internal reference buffers too - so one may not even need the ne5532.

author: Terry Bites
author_rank: Super Contributor
timestamp: April 15, 2025, 08:45:56 am
content: A 5532 has shabby DC characteristics that will kill off a lot of the precsion reference's ppmsNote that theys don't list some of the worst ones in the datasheet. Are they that ashamed?I'd drop the buffer in favour of the simple RC filter shown in the ADS1256 datasheet. I assume they have used precsion resistors for accurate DC balance or they work in a don't care about cost environment. I think a real world application will work fine with 1% MFs.If you keep the buffer opamp, you might make a second order lowpass out of it.

author: hsynylcn
author_rank: Contributor
timestamp: April 15, 2025, 09:11:48 pm
content: I have taken your suggestions into account and tried to use more up-to-date components
ads1262 test - Page 1
Forum section: electronics / projects

author: hsynylcn
author_rank: Contributor
timestamp: June 21, 2025, 09:16:54 pm
content: I built the circuit from the datasheet for the ADS1262, set the START pin HIGH and CS pin LOW. If the ADS is working, I should see a square wave from the DRDY pin. If I don't see it, does this indicate that the ADS might be faulty?

author: mtwieg
author_rank: Frequent Contributor
timestamp: June 21, 2025, 10:14:49 pm
content: Does the datasheet say that anywhere?I'm assuming you first have to write to some configuration registers before it starts to do anything useful.

author: hsynylcn
author_rank: Contributor
timestamp: June 21, 2025, 10:33:57 pm
content: I took this table from the datasheet. Here the default values are specified.

author: Simmed
author_rank: Frequent Contributor
timestamp: June 22, 2025, 02:22:02 am
content: ADS can fucntion w/o clock in ?

author: moffy
author_rank: Super Contributor
timestamp: June 22, 2025, 06:08:44 am
content: Quote from: Simmed on June 22, 2025, 02:22:02 amYes, if Pin 15 is GND and Pin 16 float, it uses an internal oscillator.It looks like you have to pulse the /CS pin each time you want to read data.

author: dietert1
author_rank: Super Contributor
timestamp: June 22, 2025, 07:22:31 am
content: As far as i read the power register default value, the device will remain in reset initially. This ADC is meant to work with a MCU for control. Without MCU it's all meaningless.Regards, Dieter

author: mtwieg
author_rank: Frequent Contributor
timestamp: June 22, 2025, 03:55:23 pm
content: There's a lot of conditions that have to be met for the ADC to operate, including register settings and pin states.I would start by trying to talk with the chip via serial commands. Read all the registers and check they make sense. Also check the status byte (strangely, it seems you can only read the status byte by reading out conversion data).

author: hsynylcn
author_rank: Contributor
timestamp: June 22, 2025, 04:09:47 pm
content: Pin 13 has dual functionality as DOUT/DRDY. I perform device selection via the CS pin. When the CS pin is LOW, Pin 13 operates in DRDY (Data Ready) mode. Under this configuration, I observed Pin 13 using an oscilloscope. While CS is LOW, a noisy square wave appears on Pin 13. However, when CS is set to HIGH, the square wave disappears.
ADS130E08 ADC Power Supply - Page 1
Forum section: electronics / projects

author: javad2040
author_rank: Contributor
timestamp: March 29, 2018, 08:48:22 am
content: I selected the ADS130E08 ADC for my project that will connect to Xilinx Spartan-6 FPGA. In Datasheet that TI offered, two configuration for power supply is recommended(Uni-polar and Bipolar) that I can't realize the differences between them. what is the differences and which way is better and stable? Note: that I want to measure ac signals with +- amplitudes
ADUM4160 Analog Devices USB Isolator,  issues with RTL SDR dongle... - Page 1
Forum section: electronics / projects

author: rwgast_lowlevellogicdesin
author_rank: Frequent Contributor
timestamp: July 10, 2014, 02:16:42 am
content: So I wanted to lower the noise floor of my SDR dongle, I decided to use an ADUM4160 chip instead of the usual technique used, which is passing the USB data lines through but isolating the power supply.Anyways I threw together an ADUM isolator on a piece of prefboard along with a 5v Linear LDO to power the isolated side of the USB. I got the ADUM4160 working just fine, I pluged some cypress devboards in no problem, next I tried an FTDI USB to serial converter, worked just fine, I also got a memmory stick and a bluetooth module working. When I plug in the RTL SDR windows is able to see it, but the Zadig driver install nor SDR sharp can see the dongle.I was wondering if anyone else has gotten a realtek dongle working with a USB isolater, and maybe specifically one based on an ADUM4160?

author: daveshah
author_rank: Unknown
timestamp: July 10, 2014, 06:47:27 am
content: Not sure if this is the problem, but those isolators only support up to full speed (12Mbps) but the RTLSDR device is a high speed device (480Mbps).

author: Scrts
author_rank: Frequent Contributor
timestamp: July 10, 2014, 04:09:40 pm
content: Quote from: daveshah on July 10, 2014, 06:47:27 amYes, this will be a problem.OP: cut the USB cable, let the USB D+/D- go through also leave the GND connected, but cut the +5V wire and use your low-noise power supply to power the dongle.
Advanced Desulfator + Pulse Car Battery Charger (AT-ATX Mod. TL494) - Page 1
Forum section: electronics / projects

author: gevv
author_rank: Contributor
timestamp: August 16, 2024, 08:01:18 pm
content: Hi,Both circuits work very well. New PCB drawings were made and boxed.https://www.eevblog.com/forum/projects/advanced-desulfator-for-lead-acid-battery-resurrection/msg5399651/
advanced electronics vibration mounts? - Page 1
Forum section: electronics / projects

author: coppercone2
author_rank: Super Contributor
timestamp: September 05, 2018, 09:56:00 pm
content: What are considered to be high end or particularly interesting ways of doing compliant mounting?I have seen the basic way is to use either spring, which should isolate, or some kinda rubber pad, which will attenuateDo they have more advanced parts like little tuned mass dampeners?these catch my eyehttp://www.andrehvac.com/blog/tag/anti-vibration-mount-wire-rope-isolator/Though, since that rope is assembled with lubricant, and it dissipates energy with friction, I wonder if you need to relube them, they might age weird.

author: m3vuv
author_rank: Super Contributor
timestamp: September 05, 2018, 11:34:51 pm
content: ive used austin mini cottonreel exauste mountings for doing this before,they work pretty well and cheap at about £1 a go,just a thought.

author: radar_macgyver
author_rank: Frequent Contributor
timestamp: September 06, 2018, 02:09:37 am
content: Barry Controls makes isolators that are suitable for low mass applications that include an air damper:http://www.hutchinsonai.com/products/product.cfm?cid=3&fid=14They also have silicone damped versions:http://www.hutchinsonai.com/products/product.cfm?cid=3&fid=17I've used the air damped version to mount crystal oscillators to avoid vibration-induced noise.

author: coppercone2
author_rank: Super Contributor
timestamp: September 06, 2018, 12:37:19 pm
content: https://www.hindawi.com/journals/jstruc/2013/658053/
Advanced ESR meter question. - Page 1
Forum section: electronics / projects

author: grant1842
author_rank: Newbie
timestamp: December 31, 2011, 04:00:17 pm
content: Hi all I am new to electronics engineering as a hobby.I am looking at a post herehttp://arduino.cc/forum/index.php?topic=80357.0.This guy did a great job on this ESR meter using an Arduino. He informs me that the current schematic and design will not get the ESR of a nf cap but will get the higher pf and up.As I work on computer MB, LCD TV, etc I would like to be able to get ESR of nf, pf, and up.So I am worndering if the current schematic can be modifed to be able to get the ESR of nf ,pf,etc ?Thanks in advance for looking at this.PSnf= Nanofaridpf= PecoFarid

author: jimmc
author_rank: Frequent Contributor
timestamp: December 31, 2011, 09:14:08 pm
content: I think you may have your multiliers confusedThe order is Farad, millifarad (mF), microfarad (uF), nanofarad (nF) and picofarad (pF) where1 mF= 0.001 F1 uF = 0.001 mF1 nF = 0.001 uF1 pF = 0.001 nFOnly electrolytic capacitors have a common failure mechanism by increasing ESR.99.9% or more of these electrolytic capacitors have a value of 1uF or more so there is no requirement for a general purpose ESR meter to operate below this value.Lower value capacitors (say less than 100nF) have plastic film or ceramic dielectrics and (almost) never fail with high ESR.There is no simple way to measure the ESR of a small value capacitor.RF techniques need to be used to prevent the reactance of the capacitor swamping its ESR.For examples of how it is measured seehttp://www.atceramics.com/Userfiles/esrmeas.pdfhttp://www.johansontechnology.com/images/stories/tech-notes/rf/JTI_Q&ESR_12-04.pdfandhttp://www.kemet.com/kemet/web/homepage/kechome.nsf/file/KEM_RF_FAQs/$file/KEM_RF_FAQs.pdf.Jim

author: grant1842
author_rank: Newbie
timestamp: December 31, 2011, 10:36:07 pm
content: Thanks for your reply.I will study the links.
"Advanced" tests to perform for a new board  - Page 1
Forum section: electronics / projects

author: Houseman
author_rank: Regular Contributor
timestamp: July 13, 2023, 03:17:59 pm
content: Hi forum.Finished drawing and routing a protoboard that consists of following blocks:#Power Supply part that generates from +12V input following voltages:-12V and +24V for the DAC part+30V and -30V for a constant current generator part+3,3V +5V +1,8V for the MCU part.# The mentioned DAC that gives me fixed Voltages outputs spanning from +12V to -24V# A constant current generator consisting of an Howland Current Pump architecture# The 8-bit MCU that governs all the above partsI must admit I have used especially for the PSU part the Webench software from TI and taken as example some evaluation boards that TI builds around their DC/DC converter that have complete schematics, calculations and routing examples.Now that the board has finally arrived from the FAB I would like to perform some tests, and apart from measuring the whole system if it's working, if the Voltages are outputted correct and so on, I would like to perform some more "advanced" test, since this board needs to be used in a lab.I am equipped with an oscilloscope, a spectrum analyzer, a 6-digit voltage meter , but I honestly don't know where to start.I admit my inexperience in this field, so if someone here can give me some points where to start, what's important to consider or even some books to read into it would be very, very appreciated.Thank You all as always.Best regards.Steve

author: ajb
author_rank: Super Contributor
timestamp: July 13, 2023, 04:23:55 pm
content: Off the top of my head, things that would be relevant for testing a power supply:- PSRR- Load regulation- Noise- Load step response- Settling time after setpoint change- Behavior with inductive and capacitive loads- How the constant current source behaves when it goes into and out of saturation- How the constant current source behaves when the load is connected/disconnected while activeA PSU that works beautifully in the middle of its range may fail catastrophically in corner cases, so repeat each of those for as many operating points as you like--testing near both ends of your expected operating ranges at very least. Any step change tests should be done with a couple of different step magnitudes as well.

author: Houseman
author_rank: Regular Contributor
timestamp: July 16, 2023, 07:09:48 am
content: Thank You so much.Excellent starting point.I will perform all those measurements and get back.Thank You again, pal
Advantest R3131: Cannot set marker frq via GPIB/serial? - Page 1
Forum section: electronics / projects

author: Yansi
author_rank: Super Contributor
timestamp: April 15, 2020, 09:09:24 am
content: Am I dumb or did they really forgot to add a command to set the marker frequency? It is possible to freely move the marker using the front panel, but hell I can't find any command to position the marker using GPIB/serial port.I see only the MF? which returns the frequency marker is at, but there is none comand I can set it remotly.Sending MF followed by a frequency does nothing.Thanks for any hints how to do it.

author: serg-el
author_rank: Regular Contributor
timestamp: April 15, 2020, 09:58:12 am
content: It depends on what you want to do.Find the peak? Easily.Sending a PS command.Read the frequency of MF? .We read the level of ML? .

author: Yansi
author_rank: Super Contributor
timestamp: April 15, 2020, 11:58:38 am
content: Finding peak is great and what not, but if I want to get the RF level at an exact frequency of interest, that for example, is not a peak? I should then try reading out the whole sample memory?

author: serg-el
author_rank: Regular Contributor
timestamp: April 15, 2020, 01:23:39 pm
content: Easily.Page 4-34.To measure the level at a frequency of 30 MHz.Give the command MK30MZGive the command ML? . RTFM

author: Yansi
author_rank: Super Contributor
timestamp: April 15, 2020, 02:00:32 pm
content: Ah great.They forgot to include the "MK" command in Table 4-8. Fuuuuuuuck."MK 405.2E6" happily moves the marker to 405.2 MHz.Thanks for the hint!

author: serg-el
author_rank: Regular Contributor
timestamp: April 15, 2020, 02:19:55 pm
content: Maybe because the MK command in table 4-7?

author: Yansi
author_rank: Super Contributor
timestamp: April 15, 2020, 04:13:02 pm
content: Well, whatever. Those tables are just mess, not a good description of commands.All is well now. Automated measurement done and working great, easing me a LOT of manual labor sifting through whole cartons of devices to test//Censored some work related stuff//
advantest r3131a power measuring failure  - Page 1
Forum section: electronics / projects

author: HIFI LOVER
author_rank: Newbie
timestamp: October 16, 2023, 03:03:27 pm
content: i have a R3131A with build in TG.Item was showing Wrong power reading on the input by 6-7 dBm. for example +13dBm on the Input from my Panasonic Signal Generator was detected only as a 7dBm signal.calibration and test gave failure; error100 (Total Gain fail) and IF Step AMP; Calibration failure.I found the same topic on Youtube by a French Technician Alan, and I changed R120 in the RF input Block from 390 Ohm to 470 Ohm (near u105) and after new calibration all passed well.After this i still have an issue; still I have a wrong readout on the input signals for about 1,7 dBm.if i make a correction in the settings by changing the REF offset to 1,7 dBm than my readout is correct.anybody has an idea if i have to allign something in the RF input Block??Like to hear

author: Renaud F5ZR
author_rank: Contributor
timestamp: February 23, 2024, 12:31:38 pm
content: Hi,Did you find a solution for that?
Advantest Spectrum Analyzer Question. - Page 1
Forum section: electronics / projects

author: sherlock
author_rank: Contributor
timestamp: January 20, 2013, 01:29:13 am
content: I've recently acquired an Advantest R3261A analyzer that doesn't display an input signal. I believe the mixer diode is defective, I measure 4-10 ohms across any two leads with any polarity with my ohmmeter. The original diode is a DMJ4317 which is obsolete. It seems that some people have been using a HSMS-8202 in place of it. The issue I see is that the cathode of the 8202 is on the opposite side of the package as the original 4317. According to the schematic both outer pads connect to ground with the center lead going to the input LPF. Would there be any difference if the diode were "reversed" from the original in this application? It doesn't appear that there's any DC voltage on any of the leads. Any thoughts?The next issue is the input LPF circuit itself. There is a break in the trace just after where the input attenuator solders to it. I can see a signal at the solder point with my oscilloscope but zero after the apparent break. See attached photo. (Photo minus the arrow was originally posted by Aurora in another thread. Thanks for letting me borrow it.)Is there supposed to be a continuous connection here? How does the signal get past this point? Any enlightenment would be appreciated.sherlock
advertize kits you will only use once in your life but will make you look pro - Page 1
Forum section: electronics / projects

author: sarepairman2
author_rank: Frequent Contributor
timestamp: September 13, 2015, 06:21:55 am
content: i just bought a grommet set.http://www.ebay.com/itm/180-Rubber-Grommet-Firewall-Hole-Plug-Set-Electrical-Wire-Gasket-Assortment-Kit-/351412984165?hash=item51d1d89965&vxp=mtrI am a proud owner of e96 decade resistor sets btw.
Advice / Feedback on buck converter /PSU layout - Page 1
Forum section: electronics / projects

author: Kryptychon
author_rank: Contributor
timestamp: July 20, 2021, 03:30:11 pm
content: Hi there,I just finished my very first layout. I appreciate any feedback and/or advice.Short description of the project:I want to convert the voltage of a LiFePO4 battery (8S, ~30V) to 9V (for further usage on a MCU board) and 12V to supply other features (like control panel and sensor boards and so on).As this will be the PSU for a small EV, I opted for 12V and chose to generate 5V or 3,3V locally if needed. These requirements lead to the shown design: Two buck converters, one feeding a 9V LDO regulator and one feeding two 12V LDO regulators. Additionally there is a simple comparator circuit to sense the temperature on the heatsinks.This is a amateur project, cost or space optimization is not an issue.Things I'm aware of:- The reverse polarity / over-voltage protection circuitry can be considered a little archaic. The main supply will always provide enough current to melt the fuse, eventually ending the reverse polarity or over-voltage condition in any case. I know that there will be ~2V reverse voltage in such a case. It looks tolerable to me.- The bypass / filter caps for the LDO voltage regulators might be omitted as they're placed "near" the PSU filter.- The free-wheeling schottky diode might be a little oversized, I opted for low forward voltage, thus I chose this generously sized part.- Heatsinks that large migh not be necessary to meet thermal specs, but (hate me for that if you like) they look cool :-)- I only need three temperature sensors but I decided to implement all four channels of the LM339 for temperature sensing.Concerns:- It feels like I messed up the layout around the LM339 thus "needing" a second layer. Can anyone see a more elegant way of routing and maybe avoiding using the second layer for the "12V_OUT2" track/net?- As I'm a little insecure about proper low impedance grounding, I chose using two ground planes and (excessively) stitched them together.- The data sheet of the LM2678 advises to keep the feedback track away from the inductor field. On the other hand, the current loops should be as short as possible, this leads to compromises in the layout. Is the feedback track far enough from the inductor?- It felt like an good idea to spare the ground planes under the inductor, so it cannot induce currents in the groundplane. On the other hand, it disrupts the ground plane in a large area of the board. What do you think?Attached you'll find the component layout, the two layers layout and the schematic.Best regardsKryp
Advice for a waveform generator - Page 1
Forum section: electronics / projects

author: walou
author_rank: Newbie
timestamp: December 02, 2017, 09:30:21 am
content: Hello,I am looking for an arbitrary waveform generator that is able to generate this kind of signal and that can be triggered:Do you think that the Rigol DG1022Z or the Rigol DG1032Z could do the job ? I'd take other suggestions in the same price range.I know those models are overkill for this job but I will need them for other purposes,Thanks,walou
Advice for Wall Control for refrigeration system - Page 1
Forum section: electronics / projects

author: jbomba
author_rank: Contributor
timestamp: March 10, 2013, 04:55:53 am
content: Hi guys can anyone give me some advice on a wall control unit? I am designing a refrigeration system. I need the controller to have 4 temperature sensor inputs. and 4 outputs 24vdc or 240vac that will drive relays. I also need an indoor control panel with on/off button setpoint control and the ability to display my 4 inputs. A google search didnt bring up anything

author: Thor-Arne
author_rank: Unknown
timestamp: March 10, 2013, 07:17:15 am
content: Atmega/arduino and a few DS18B20 temp sensors, a few tactile switches a LCD display.Relay output through some driver transistors, nothing particular complicated.
Advice me how to mill the boards - Page 1
Forum section: electronics / projects

author: miceuz
author_rank: Frequent Contributor
timestamp: March 15, 2014, 09:22:31 pm
content: I want my boards to have smooth edges. I've tried making tabs and adding v-scoring so the tabs would break clean (see the pic), but this does not work - I get ugly bumps on the boards anyway. Can anyone suggest me how to solve this?How is it done in a proper production environment for funny shaped boards? Are the boards milled out after pick-and-placing them?

author: I_may_be_drunk_right_now
author_rank: Contributor
timestamp: March 16, 2014, 01:25:57 am
content: You put "snakebites", ie non-plated drill holes in a pattern, slightly recessed from the edge of the PCB.http://www.adafruit.com/adablog/wp-content/uploads/2012/11/Figure-2-Breakaway-Perforation-Locations1.pngClear?

author: miceuz
author_rank: Frequent Contributor
timestamp: March 18, 2014, 07:03:40 pm
content: Thanks for reply, that might work, but it will leave rough edge at the spor anyway, won't it? What's the recommended size for a hole?

author: michaelym
author_rank: Regular Contributor
timestamp: March 18, 2014, 07:22:05 pm
content: For real "smooth" edges I think you will need to sand it down after production.

author: Harvs
author_rank: Super Contributor
timestamp: March 18, 2014, 10:47:08 pm
content: It all depends on if you have to pannellise them. If you can get away with assembling the individual boards, then you just need to get fully routed edges.
Advice needed about step-down regulator - Page 1
Forum section: electronics / projects

author: r-s
author_rank: Unknown
timestamp: August 07, 2020, 03:06:43 pm
content: Hey everyone,I'm working on a few projects for which I need a step-down power supply. In the past I could always rely on an external supply, so I don't have any practical experience with DC-DC converter circuits and could use some advice.Here's some context:The load requires between 9 and 24 Volts, depending on the project. This is provided by an external power supply (some readily available wallwart).The control part (ESP32 plus some other stuff) runs on 3.3 V. As I don't want two external supplies, I need a regulator. A linear regulator would waste way too much power, so a step-down regulator is required.These are hobby projects; I'm not going to sell them => regulations (e.g. about EMI) aren't that important.I want one general purpose 9-24 V to 3.3 V step-down circuit (max. Iout: 2A), instead of one optimised circuit per project. As a hobbyist, I'd rather spend a few cents more than needing a huge inventory of parts that are only used in one project.Requirements for the step-down circuit:Reasonable efficiency. I'd really like >90%, but don't think that's realistic when stepping down from 24 V to 3.3 V.Small footprint area; I'd like to keep the PCB small.Maximum part height: about 10 mm.Must be solderable with iron or hot air rework station. I can handle QNFs and similar packages. Grid arrays (LGA, BGA) I want to avoid.I looked around for ready-made power modules. Recom has a few nice 3-pin THT devices, however above 1A they are just too high; the smaller parts all have grid arrays.I browsed Digikey, but haven't found anything nice that matches my requirements. Maybe I've missed something? If someone could point me to suitable modules, that would be great.Assuming I'll have to build the circuit myself, I could need some advice:Which regulator ICs should I consider?I had a look at TI's parts with integrated inductor (e.g. TPSM53602). Those look nice; the integrated inductor keeps the footprint small. Any reasons to go for an external inductor instead?Any other TI parts I should consider? I particularly like TI, as I find WEBENCH quite helpful.Any other manufacturers I really should have a look at? The manufacturer should have a tool similar to WEBENCH.How much should I care about EMI? WEBENCH offers EMI input filter circuits (CISPR 22 and 25). Should I add such a filter? As mentioned above, I just want to avoid causing any interference for myself or my neighbors, so how much filtering is enough?And finally: are there any other important questions that I should ask but haven't so far?Now please let the advice flow; I could really use itCheers,Rolf
Advice on calibrating an RC lipo testing thingy I've put together? - Page 1
Forum section: electronics / projects

author: Northy
author_rank: Regular Contributor
timestamp: January 15, 2022, 04:58:08 pm
content: Hi,I've built a testing set-up to test RC lipos to try and get an idea of how they are holding up to the abuse they get while being used.By connecting an external resistor bank to my charger I can discharge them at up to 20A, this is done by connecting the battery under test to the input of the charger and the resistor bank to the charging port. I've got this bit working fine.While the battery is discharging I monitor it with a Picologger.The batteries are 2S, so have a centre 'balancing' terminal. So with the Picologger I am using two channels to log the centre tap point and the +ve terminal - both with respect to the -ve terminal.In the Picologger software I log the overall pack voltage, the centre tap voltage and then subtract the centre tap voltage from the overall voltage to log the second individual cell voltage.I'm getting a small discrepancy between the two individual cell voltages, that I'd like to calibrate out as much as possible in the software logging. I'm not looking for absolute, traceable calibration here, just good enough to see if I've got a bad battery or not.All I've got to hand is a variable bench power supply and a few hand-held meters. None of them calibrated themselves. I don't have access to any calibrated equipment either.What's the best way to try and get my set-up as good as I can, with the equipment I've got?Thanks,G

author: IanB
author_rank: Super Contributor
timestamp: January 15, 2022, 05:06:32 pm
content: It is intended that you can trust the readings on the hand-held meters. You don't need a calibration certificate except for specific traceability requirements. Therefore, just use a meter to measure the voltages and adjust accordingly.What I typically do if I have a few hand-held meters is to measure the same voltage on all of them and compare readings. Any meters that are deviating significantly from true will typically be revealed by giving outlying readings.

author: Northy
author_rank: Regular Contributor
timestamp: January 18, 2022, 10:46:50 pm
content: Hmmm, yeah, maybe I was thinking too much about itThanks,G
Advice on conformal coating - Page 1
Forum section: electronics / projects

author: daqq
author_rank: Super Contributor
timestamp: March 08, 2019, 09:10:23 am
content: Hi guys,We will be doing a conformal coating of a PCB. The PCB contains lots of stuff, but the iffy part are several diodes in a MINIBLOC package ( similar tohttp://ixapps.ixys.com/datasheet/dsei2x30-04c_dsei2x31-04c_dsei2x30-06c_dsei2x31-06c.pdf).We can use two approaches:- spray/dip coat the fully assembled PCBwiththe diodes screwed on.- spray/dip coat the PCBwithoutthe diodes screwed on.Either way we shall be masking a few parts of the PCB since there are contacts that must remain exposed either way.I'm for dip coating the PCB without the diodes screwed in and screwing them in later. A colleague is for the other option.What is the proper way to do this? A PCB with screw on power parts?Thanks,David

author: tszaboo
author_rank: Super Contributor
timestamp: March 08, 2019, 11:11:59 am
content: I'm 90% sure the thermal expansion of those terminals is going to break apart the conformal coating after a while.I used these in the past, It is not even that simple to just scew it in and done.

author: daqq
author_rank: Super Contributor
timestamp: March 08, 2019, 12:58:29 pm
content: Thanks for the info. The conformal coating is fairly flexible (Electrolube HPAhttps://www.electrolube.com/pdf/tds/044/HPA.pdf), so cracking should not be that much of an issue.

author: tszaboo
author_rank: Super Contributor
timestamp: March 13, 2019, 01:54:26 pm
content: Wait, you are not applying the coating on the screw then? Might have misunderstood that.I would not dip the SOT227 parts into the coating in any case, since the bottom of it has to be thermally conductive to the heatsink below it.

author: daqq
author_rank: Super Contributor
timestamp: March 16, 2019, 06:54:47 pm
content: QuoteI would prefer not to. My colleague has a different opinion. My preferred option would be to mask all the PCB, coat the PCB, remove the masks and assemble the diodes.QuoteThe diodes won't be needing a heatsink at all, given that they are only used for their pulsed characteristics (the average power on them will be less than 1W (the peak pulse power will be much higher).

author: nctnico
author_rank: Super Contributor
timestamp: March 16, 2019, 07:16:56 pm
content: My gut feeling says to make sure the screws are not covered with conformal coating. There is probably a spring washer under the screw and the conformal coating can keep it from doing it's job.