hybridfree/eevblog-posts huggingface dataset:
LTC3803 Flyback, isolated, various inductance ratios - Page 1
Forum section: electronics / projects

author: 741
author_rank: Frequent Contributor
timestamp: March 23, 2021, 05:07:24 pm
content: I'm wondering how to make the feedback more accurately control the main output.One thing I notice is if I raise the capacitor on the feedback winding, the isolated output exhibits slow, large oscillations.When I omit the feedback winding, and use feedback from the output, the output level is pretty accurate - consistent with the feedback network.But using the feedback winding for feedback gives a large discrepancy in expected main output voltage.In this design, the feedback winding has twice the inductance of the output winding: L(feedback) is twice L(secondary). Therefore I expect the output voltage to be 1/SQRT(2) times the feedback voltage. But it is considerably lower than that.I could simply keep trying feedback ratios until I see the required result, but that seems unsatisfying.I tried raising the main load resistor by 10x, but no useful gain in accuracy was seen.I also tried making all windings the same inductance - I'd expect FB_OUT to be the same as OUT then. This works quite well (the discrepancy is less).UPDATE:Noticed the feedback coil is not peaking but the voltage after the diode is (!). It seems it relates to the diode speed or something? Results a bit better with a fast silicon - lower spike after the diode. I had thought Schottky, having no stored charge, would be better.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 23, 2021, 07:07:31 pm
content: Put a heavier load on the FB winding. Congrats, you've discovered cross regulation and why it sucks.Curiously, you're having such poor results even with K=1, a parameter that will definitely not survive in the real world. That is, cross regulation is degraded by K < 1 (or leakage inductance, however you like to express it).Ed: opening up the sim, it's low by a volt. Which is the voltage drop of the rectifier and filter cap (was the ESR specified as 1 ohm intentionally?). You're just way too picky. It's within 10%, which is better than you can hope for IRL.I find the ESR particularly disturbing, as C6 specifically has none and has an explicit resistor in series with it?The time constant of the feedback network determines compensation. It should be a similar time constant to the output; but of course, this cannot in general be ensured while the load resistance varies. All the more reason to drop in an opto and TL(V)431 as is usually done.Tim

author: 741
author_rank: Frequent Contributor
timestamp: March 23, 2021, 09:05:23 pm
content: Ah, the secondary has heavier current so greater diode drop?I removed the chip to look at the diode spike thing.
LTC4020- Battery Charger - charge/ discharge current - Page 1
Forum section: electronics / projects

author: tej93
author_rank: Newbie
timestamp: April 28, 2017, 07:13:13 am
content: Hello,I am designing 12v Battery charger using LTC4020. from datasheet of IC, i found charging current to battery will be programmed by Rcs current sense resistor between CSN and CSP pins. so i want to know that can i design circuit in such way that i can have different charging and discharging current. for example if i set charging rate to 4A then may i have discharging greater than 4A let say 8A or anything else?
LTC4020 Charger issues - Page 1
Forum section: electronics / projects

author: brinbrin
author_rank: Newbie
timestamp: September 09, 2015, 02:38:28 pm
content: I am designing a battery charger for 4 LIPOs using LTC4020 as the controller. I am going through a world of hurt getting it to work. So far I have got the chip to indicate its charging and everything is OK but nothing much happens. The input mosfet turned on by TG1 does not come on at all. Am sure I have done something silly, if anyone has any ideas I am all ears.I have attached the schematic of concern

author: SaabFAN
author_rank: Frequent Contributor
timestamp: September 09, 2015, 03:49:33 pm
content: From a first glance, without checking the datasheet, I would say that you forgot to connect the BOOST-Circuit to Vin.

author: brinbrin
author_rank: Newbie
timestamp: September 10, 2015, 03:03:29 am
content: When VIN is lower than VOUT during step-up (boost) operation, switches Q4 and Q5 perform the PWM required for accommodating power conversion. Q2 wouldconduct continuously and Q1 would stay off,

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: September 10, 2015, 03:19:56 am
content: Hi,Do you have something connected to the NTC pins?Try a 10K resistor on the NTC pin to ground.Jay_Diddy_B

author: brinbrin
author_rank: Newbie
timestamp: September 10, 2015, 03:21:59 am
content: When nothing is connected to the ntc pin it still should work, in my case i have hooked up a typical 10k thermistor
LTC4162 Battery Charger Design  - Page 1
Forum section: electronics / projects

author: bbqstingray
author_rank: Newbie
timestamp: November 30, 2021, 11:33:10 pm
content: Hi all,Could you guys take the time to critique my LTC4162 Design.I have going to hook it up to a 7S1P LiFePO4 battery pack that will output ~22.4V.I plan to connect the output to a step-down regulator LM5118 at 12V.I am unsure if its best to have a 4 layer board or 2 layer board for this application.Thank you for taking to time to look at my post.Datasheets:LTC4162https://au.mouser.com/datasheet/2/609/LTC4162_F-1371182.pdfhttps://www.analog.com/media/en/dsp-documentation/evaluation-kit-manuals/DC2038A.pdfInductor:https://au.mouser.com/datasheet/2/597/xal60xx-270658.pdfMOSFETCSD19534Q5Ahttp://www.ti.com/lit/gpn/csd19534q5aSchematicPCB Layout
LTC4267-1 POE 12V design Output issue - Page 1
Forum section: electronics / projects

author: moonsunshoot
author_rank: Newbie
timestamp: August 19, 2021, 09:07:23 am
content: Hi all,I have done the design as per the LTC4267-1 application circuit and I am using the PA1135NL 12V output transformer, But Getting 3.3V output only, Can anyone please help with this issue. I have attached the design here.

author: fcb
author_rank: Super Contributor
timestamp: August 19, 2021, 09:27:18 am
content: Immediate suspicion is that R23/R29 network is wrong.Quick calculation shows that it should regulate VCC12V0 to about 6.6V, but this is not 3.3V as you have found.Probably check all your rails (including PVCC), scope out ITH/RUN pin and check switching frequency assumptions. Post pic of PCB, layout, etc.. Does the 3.3V hold up under load? Is it regulating correctly?

author: moonsunshoot
author_rank: Newbie
timestamp: August 19, 2021, 09:55:53 am
content: I'm getting constantly exact 3.3V, even output is connected to load. i have changed PA1135 to PA1133 transformer also, but still 3.3V!

author: fcb
author_rank: Super Contributor
timestamp: August 19, 2021, 03:51:32 pm
content: Ha. Just looked up the datasheet for the exact D14 (ZR431LF02TA). This version of the venerable TL431 is 1.24V.So at regulation you'll get 1.24V (+/- 2.5%) across R29 (60.4K), so 20.53uA flows through R29. Which means you'll get the same current through R23, which in-turn means the VCC12V0 rail must be sat at 3.29V (1.24V+(20.53uA*100K)).So your circuit is acting correctly.If you want 12V, you need to change the R23/R29 ratio.So perhaps change the 60.4K to 11.5K (E48 preferred value) and you should get 12.02V

author: moonsunshoot
author_rank: Newbie
timestamp: August 20, 2021, 05:34:52 am
content: Thank You fcb,Let me make the changes in R29 as 11.5K and check the output, I hope should get the output 12V now!
LTC4412 ideal diode alternative - Page 1
Forum section: electronics / projects

author: OwO
author_rank: Super Contributor
timestamp: April 05, 2019, 03:29:46 pm
content: On taobao/aliexpress there are these ideal diode modules using a SOT26 controller and two MOSFETs:Looking around the only ideal diode controller I can find in SOT26 is the LTC4411/LTC4412, but the price of the controller chip (even taobao prices) alone exceeds the price of these modules. I'm wondering if anyone knows what controller part number they are using on these modules.TL;DR: I'm looking for an ideal diode controller like the LTC4412 but at more reasonable prices.

author: Kalvin
author_rank: Super Contributor
timestamp: April 05, 2019, 08:38:14 pm
content: Maybe this one:https://www.ic-fortune.com/upload/Download/DW01-G-DS-10_EN.pdfPrice at Aliexpress: $3.26 / 30 pcs.Edit: If the MOSFETs are P-type, then the controller is not DW01 as it is designed to be used with N-MOSFETs.

author: jbb
author_rank: Super Contributor
timestamp: April 05, 2019, 09:38:25 pm
content: Intersil doesa couple of ORing controllers. They include charge pump drivers for high-side NMOS switches. I've used the ISL6146 in a USB design and it does what it says on the tin.Note that the quiescent and operating currents may be an issue, so check those parameters for whatever you pick.

author: OwO
author_rank: Super Contributor
timestamp: April 06, 2019, 04:46:17 am
content: Quote from: blueskull on April 05, 2019, 06:12:06 pmI'm looking for general purpose ORing controllers for 3 to 10V, 2A max, and ~1us switching.The two use cases are:(1) Simple solar battery charging for small devices, I need to prevent backflow from battery to charging buck converter and quiescent current on the battery side (output side) must be low (~10uA).(2) Automatic power source switching for USB devices with builtin battery, where attaching USB power should switch power source from battery to USB with no interruptions.The controller should be around $0.5 or less.

author: jbb
author_rank: Super Contributor
timestamp: April 06, 2019, 06:13:19 am
content: For the USB / battery powered device, is it a rechargeable battery? If so, I suggest you find a charger with PowerPath. They’re better at charging the battery than just hanging the system load straight off the battery and include a changeover switch for you.
LTC6268 Noise calculation and simulation - Page 1
Forum section: electronics / projects

author: arivalagan13
author_rank: Contributor
timestamp: October 28, 2020, 05:08:48 pm
content: Hi allI'm designing a Transimpedance amplifier of gain 250 x 10^6 with LTC6268 500MHz gain bandwidth product version. I want to calculate the noise and simulate it with LTSpice. My bandwidth of interest is from 10 Hz to 5 kHz.I need some clarification regarding the noise calculation. The datasheet table mentions that the 1/f noise between 0.1 to 10Hz is 13 uV p-p.. but the corner frequency where 1/f and broadband noise meets is 80 kHz... But my bandwidth of interest is well within this 80kHz mark. Also, there is no graph to find the 1/f noise..only it is shown as RF amplifier. Can someone please shed some light on noise calculation on this amplifier. Thanks

author: Wimberleytech
author_rank: Super Contributor
timestamp: October 29, 2020, 06:46:59 pm
content: I integrated the 1/f from .1 to 10 and got a p-p around 16uV--not 13uV
LTC6811 & LTC6813 - work with different frequency conversion - Page 1
Forum section: electronics / projects

author: lorenrus
author_rank: Regular Contributor
timestamp: June 30, 2021, 07:06:44 am
content: Hello,I am using the LTC6813 and LTC6811 in parallel. I would like to set a different conversion rate for GPIO and Cells. When I set it differently, what I get is a PEC error, but when I set them the same no. Poetet help me understand? Thank you
LTC6943 datasheet wtf - Page 1
Forum section: electronics / projects

author: CopperCone
author_rank: Super Contributor
timestamp: January 04, 2018, 12:30:47 am
content: I want to build the programmable gain amplifier listed in the datasheet. I have no clue what they are referring to however:What is 14A and 14B?http://cds.linear.com/docs/en/datasheet/6943f.pdf

author: CopperCone
author_rank: Super Contributor
timestamp: January 04, 2018, 12:39:32 am
content: never mind, I understand, you need two chips. Most of the other examples use only one part.

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: January 04, 2018, 12:51:31 am
content: The 6943 is a "clone" of the ltc1043. So look into that datasheet for more information/confusion.There is a similar circuit there which might guide you.The only reasonable thing given the functionality is that 14A is the clock input. (But 14B is the same in that case, so definitely strange!).The ltc1043 datasheet has the same circuit using labels 16A and 16B. Again, it seems to refer to the clock.So, right, it seems to be a roundabout way of telling us that, even though you only need two switches, each has a separate clock, so you actually need two devices. You end up with two unused switches. Oh well.Good luck! Let us know if you get it to work.

author: CopperCone
author_rank: Super Contributor
timestamp: January 04, 2018, 02:20:44 am
content: What does the SHA pin even do? I cant find it in either datasheet (lt1043 or 6943).Going to be a while before I get any thing working. Months before I have a PCB made.

author: harry dB
author_rank: Newbie
timestamp: July 21, 2024, 10:59:00 pm
content: If anyone has any information on the purpose of the SHa and SHb pins, do please let us know. I've gone through the datasheet of both the LTC1043 and the (https://www.analog.com/media/en/technical-documentation/data-sheets/1043fa.pdf) and the purposes are nowhere to be found. It's kind of implied that they are shorted to the Ca- and Cb- pins, but that doesn't make sense of course

author: moffy
author_rank: Super Contributor
timestamp: July 22, 2024, 12:34:38 am
content: Quote from: harry dB on July 21, 2024, 10:59:00 pmHard to find, but it is used to provide a guard ring in the CMRR test, see attached photo from the datasheet:P.S. The SH probably stands for 'shield'.
LTC6992 - PWM Generator Implementation? - Page 1
Forum section: electronics / projects

author: ryanmills
author_rank: Unknown
timestamp: September 29, 2020, 02:04:38 am
content: Relevant Datasheets Linked below. I'm trying to create a simple and small motor driver board based around the DRV8871DDA. To drive it's PWM input I am trying to use the LTC6992. It has a handy calculator athttp://beta-tools.analog.com/timerblox/LTC6992that I have set the supply voltage to 5v and freq to 20kHz. Now if I am reading the datasheet correctly driving the MOD input from 0v to 1v will drive the duty cycle from 0 to 100%. Question is since it should not really draw current can I drive that using the 5v rail and a pot? I think I did my math correctly for the voltage diver so it should give me a range from .1v to 1v going into the MOD pin using the pot at R3. Could this work with a little 1/2 watt pot? Schematic attached.DRV8871DDA (Motor Driver):https://www.ti.com/lit/ds/symlink/drv8871.pdfLTC6992CS6-1#TRMPBF (PWM GEN):https://www.analog.com/media/en/technical-documentation/data-sheets/LTC6992-1-6992-2-6992-3-6992-4.pdf

author: ryanmills
author_rank: Unknown
timestamp: September 29, 2020, 06:51:36 pm
content: I'm assuming my idea was so bad no one wants to even comment. Any suggestions on a low footprint way to get the .1 to 1 volt signal from the 5v rail? Space is very limited.

author: julian1
author_rank: Frequent Contributor
timestamp: September 29, 2020, 08:39:26 pm
content: I used the LTC6992 as a pwm generator in the past. I don't remember the pin-out well enough to comment on your design, but found that following the datasheet everything worked as expected and there were no surprises. Using a resistor divider, trimpot, or voltage feedback for a simple voltage regulated smps, duty cycle control in the 0-1V range all worked. I used a 2.54mm pcb breakout, and prototyped on a breadboard.

author: Hiemal
author_rank: Regular Contributor
timestamp: September 30, 2020, 12:46:08 am
content: Yeah, will add, that sounds like it'll work fine. Your mod pin only requires about 10 nA of input bias to function properly, so unless you're using some insanely high resistances you should be okay.

author: ryanmills
author_rank: Unknown
timestamp: September 30, 2020, 09:09:27 pm
content: OK thank you both, I will order some prototypes and see what happens.
LTC7061 shoot-through problems, dead-time seems to dissapear? - Page 1
Forum section: electronics / projects

author: Verspecke
author_rank: Newbie
timestamp: May 12, 2025, 08:37:59 am
content: Hello everyone,Currently I am trying to design my own H-bridge drive circuit for a 24V brushed PMDC motor (195W), but I'm experiencing shoot-through issues with my NMOS half bridge driver which I do not know how to solve.In the attachments I have included a screenshot of my circuit in LTspice, the LTspice simulation file, datasheets of the motor, LTC7061 (driver) and IRF1010EZ (NMOS) and screenshots which indicate my problem.In the simulation I am running the H-bridge in one direction by giving BOT2 a DC signal of 3,3V, TOP2 gets no signal which pulls it to ground due to the LTC7061's internal circuitry, TOP1 gets a 20kHZ signal with a duty-cycle of .5 to chop 50V -> 25V (easier to interpret simulation waveforms then 24V @ D=.48) and BOT1 is being activated after TOP1 to make sure the current will not return to the supply (since I will be using a bench power supply at the beginning).According to page 10 of the LTC7061 datasheet, the maximum amount of dead-time (250ns) can be introduced by leaving the DT input floating, which I did and shows in images 1.png and 2.png (input signals vs gate signals). When comparing TG to TOP1's vgs and vds (image 3.png) it seems to do its job fine, but when comparing BG to BOT1's vgs and vds (also image 3.png) it appears as if vds doesn't follow vgs, but instead switches exactly at the same time as the TOP1 vds which introduces a gigantic current spike because of the shoot-through.I don't understand why this happens, and how to stop this effect? And also, why it only happens at the transition TOP1(off-on) -> BOT1(on-off) while TOP1(on-off) -> BOT1(off-on) also overlap in vds while transitioning? It appears as if the dead-time dissapears or is simply not implemented.If I didn't provide enough information or attachments, please let me know and I will try to respond a.s.a.p.Thanks in advance,Colin

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: May 12, 2025, 03:44:13 pm
content: Hi,The shoot-thru current is the from the body diode recovery. The body diode in the bottom MOSFET is conducting when the top MOSFET is turned on.This model gives the same shoot-thru current without the LTC7061.The simulation model does not include any inductance. The diode is being recovered with a very high di/dt.Regards,Jay_Diddy_B

author: Verspecke
author_rank: Newbie
timestamp: May 13, 2025, 09:40:06 pm
content: Thanks! I finally understand.
LTC7878 simulation doesn't match reality - Page 1
Forum section: electronics / projects

author: sapien
author_rank: Contributor
timestamp: March 31, 2025, 04:06:11 pm
content: Designed and build an LTC7878 based battery charger, with 2 in parallel, and Vout and Iout set by an MCU externally.I've done, to my knowledge, quite extensive simulations in LTSpice, especially with regards to control loop stability. Because it's a battery charger, I've tuned down the gains a bit compared to the development board, since a dip in voltage isn't causing brown-outs for example.However, the simulation results don't match reality, where I see oscillations (+- 48Hz, but depending on input voltage). These oscillations show up in the output voltage, and on the ITH pin (ErrorAmplifier Compensation Point). The scope figure shows the ITH voltage.These oscillations seem so incredibly slow, that I feel like parasitic capacitance and/or inductance from my PCB design shouldn't be the culprit.... right?I've measured RUN, Soft-start, INTVCC, DRVCC, CLKOUT and they all seem to operate as expected. The oscillation frequency depends on the input voltage, shifting about 4 Hz when going from Vin 13V to 20V, with Vout at about 14V, so I don't think it's 50Hz grid noise related.Where could the differences between the simulation and measurements originate from?

author: Terry Bites
author_rank: Super Contributor
timestamp: March 31, 2025, 05:22:28 pm
content: I dont see a load for this circuit.

author: sapien
author_rank: Contributor
timestamp: April 01, 2025, 07:42:10 am
content: Correct, currently I don't have a load configured - both in real life and the simulation. Could that give trouble in practice?

author: mtwieg
author_rank: Frequent Contributor
timestamp: April 01, 2025, 11:08:39 am
content: So you're seeing these oscillations only in the real circuit, not in simulation?The only waveforms you shared are from the simulation, so there's not much to comment on...Sharing your .asc file may also help.Quote from: sapien on April 01, 2025, 07:42:10 amAs far as I can tell, the LTC7878 can only control power in one direction, so it's unclear how it could possibly oscillate without some sort of DC load...
LTO Lithium battery protection questions - Page 1
Forum section: electronics / projects

author: 3roomlab
author_rank: Frequent Contributor
timestamp: February 07, 2018, 06:36:12 am
content: after trying to look for "titanate" type protection (Over/Under-volt lock out), it seem there are no prefab chip solutions. so i tried to LTspice it.question is, is this sketch the norm? especially for a basic OV/UV?(for titanate type cells which hovers around 2.2-2.4v)any tips welcomed and appreciated
LTO lithium titanate battery BMS troubles - Page 1
Forum section: electronics / projects

author: mikemoy
author_rank: Newbie
timestamp: October 13, 2022, 04:07:48 am
content: Designing a new product where I need a rechargeable battery for low temp applications.The LTO batteries are well suited for low temp applications.I have searched and searched and I cannot find any circuit or IC to make a BMS or at the very minimum a low voltage protection for these batteries.Has anyone worked with these before that might be able to suggest something.FWIW, Not looking for a off the shelf product but more in the way of IC's so I can add the circuit to my PCB.Cell Max: 2.8Cell balance: 2.75Cell Min: 1.5Thanks!

author: Ice-Tea
author_rank: Super Contributor
timestamp: October 19, 2022, 04:30:06 pm
content: Have a look at TI's portefollio. You can select minimum battery voltage in the selector so that should help you get some parts that are perhaps configurable enough to fit your needs.
Ltspice alternative for AD797 - Page 1
Forum section: electronics / projects

author: john23
author_rank: Frequent Contributor
timestamp: February 25, 2025, 08:04:19 am
content: Hello , is there an alternative I could use for AD797 , LTspice model will be best.The model I got is very bad and its oscilating for no good reason.Thansk.https://www.digikey.com/en/product-highlight/a/analog-devices/ad797-low-noise-distortion-operational-amplifierGain bandwidth: 100 MHz-3 dB bandwidth: 8 MHzVoltage input offset: 10 µV, 25 µVDual voltage supply: ±5 V to ±15 V

author: mtwieg
author_rank: Frequent Contributor
timestamp: February 25, 2025, 04:45:26 pm
content: Quote from: john23 on February 25, 2025, 08:04:19 amLTspice doesn't seem to have AD797 in its built-in library, what model are you using then?What version of LTspice are you using?Why do you think the oscillation is because of a problem with the model and not your circuit? It has a compensation pin which needs to be used properly to get good results...

author: Zero999
author_rank: Super Contributor
timestamp: February 25, 2025, 11:00:37 pm
content: According to the other thread, he isn't using the compensation pin.https://www.eevblog.com/forum/projects/proper-way-to-connect-signle-ended-to-differential-circuits/msg5828103/#msg5828103
LTspice and Roman Blacks 2 transistor SMPS - Page 1
Forum section: electronics / projects

author: lk
author_rank: Regular Contributor
timestamp: November 29, 2012, 06:46:06 pm
content: Greetings,I find thishttp://www.romanblack.com/smps/smps.htmSMPS fascinating, so i made as close a copy as i could do in LT Spice, and i found something curious, the total power going into the circuit is around 6.5 watts and the energy output is 5,67 watts, that's around 87% efficiency which is think is very nice, but my problem is that Q3 in my Simulation(Q1 in RB's) is listed as having a dissipation of 6.1 watt, i don't understand this, it would surely destroy a to-92 package. For one if i cannot count on the energy dissipated in that transistor, it will be hard to make changes to the circuit, and then trust the numbers.-lk

author: c4757p
author_rank: Super Contributor
timestamp: November 29, 2012, 07:16:16 pm
content: I built the circuit in LTSpice with a 4.7V Zener (1N750) - 3.75V output - and a 100 Ohm load. I am getting a peak power in that transistor of 1.8W, but if I ctrl-click the waveform expression, it shows an average power of 6.33mW. The peak collector current is -430mA at startup and -220mA once it has stabilized, which is well within the maximum for most higher-power TO-92 transistors. The maximum power is related to the maximum temperature, so it's the average that will damage the transistor, not the peak.

author: lk
author_rank: Regular Contributor
timestamp: November 30, 2012, 07:33:45 am
content: Thanks c4757p, i have been ctrl clicking my waveforms, and i can see that the collector current is averaging at 250mA(the bc327 is rated at 500 average) so i guess it should be alright even at a load of 500mA, but I'm still confused in regards to the shown power dissipation.-lk

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: November 30, 2012, 07:58:01 am
content: The average power of Q3 says 437mW from your simulationSo you are near the limit with a to92.I have used this circuit to step down and power my controller ic on some boards, it works well and is very cheap but it takes a bit of soldering. I am only using about 70mA I think.I seem to remember that, maybe?? Hero999 did some variation of it, and he is sometimes on this forum.

author: c4757p
author_rank: Super Contributor
timestamp: November 30, 2012, 04:55:27 pm
content: I didn't noticed you include the LTspice file for the version you tried. I just downloaded it and played with it.Try playing around with the base resistor for that transistor, it is not the best value. I got the power down to 500mW average with no detriment to the output quality by increasing it to 2k, and you could probably do better (my laptop is running on fumes right now, I'm out of time...)
LTSpice Automation - Page 1
Forum section: electronics / projects

author: Glenn0010
author_rank: Regular Contributor
timestamp: February 12, 2023, 01:56:12 pm
content: Hi All,I've tried looking online but cannot find any clear-cut answers.I'm running a simulation and want to do an FFT of a (two measurements multiplied together).The way I do it now is to open the measurement, right click press view FFT enter the parameters.Is there a way to automate this FFT measurement via some commands or spice directives?I've seen that some people use python to automate some stuff however cannot find the answer to my question.Cheers GG

author: mikerj
author_rank: Super Contributor
timestamp: February 12, 2023, 02:09:25 pm
content: The .FOUR command will dump the amplitudes of a specified number of harmonics to a log file, which might be useful for you.
ltspice - can text run from top to bottom? - Page 1
Forum section: electronics / projects

author: ledtester
author_rank: Super Contributor
timestamp: September 26, 2022, 05:28:48 pm
content: I was exploring all of the possible text orientations and it seems that vertical text can only run from bottom to top.Is that correct or am I missing something?

author: Ian.M
author_rank: Super Contributor
timestamp: September 26, 2022, 06:05:17 pm
content: It can't do upside down text either . . .If you are looking for a schematic drafting package to prettify your circuit for publication, LTspice is *NOT* it!

author: ledtester
author_rank: Super Contributor
timestamp: September 26, 2022, 07:13:14 pm
content: Thanks!No, I'm not trying to use ltspice to do that -- just delving into the particulars of the .asc file format.
LTSpice - chime's ding simulation - solved - Page 1
Forum section: electronics / projects

author: atferrari
author_rank: Frequent Contributor
timestamp: January 21, 2015, 02:03:29 pm
content: SOLVED BY ADJUSTING ATTACK TIMING.I intend to replicate the sound of a simple clock's chime. So far, using LTSpice, I managed to control attack and decay times.Please check the sound in the attached .wav file. I understand that kind of a thump is perceived at the start, which I find annoying and far fom nice.The signal, taken at the output after several DC blocking caps looks as shown. Really.My questions:1) Do you agree on the initial anomaly? My hearing is definitely bad so I do not trust much on what I perceive.2) If so, is it an artifact created by LTSpice when sampling the signal and passed into the .wav file?3) Or is it that initial jump of around 300 mV pk-pk, the reason of it?4) Or just my sound card?Comments appreciated.
ltspice crystal equivalent circuit .tran vs .ac simulation - Page 1
Forum section: electronics / projects

author: MD1071
author_rank: Newbie
timestamp: November 06, 2024, 11:23:23 pm
content: hey all,I'm trying to simulate the equivalent circuit of a crystal oscillator. Its a simple RLC circuit with a shunt capacitor. I first did a .ac frequency sweep and saw the expected resonance peaks and at the correct frequency. However when I did a .tran measurement by using a sine wave with the resonant frequency, I get a phase shift of zero!*note--> sorry just noticed the different labels. V(n002) is the node above the right most capacitor in both the circuitsV(n001) is the node right after the 150k resistorthe .ac plots show that phase shift at 50.948KHz should be ~-84 deg --> this is phase difference between n001 and n002 or the top shunt capacitordoing .tran I see the phase difference as 0. I've tried timesteps as small as 0.01u but still see zero phase shift. if I use a smaller value of shunt capacitor from 2.0789p to something < 0.1p then I can see some non-zero phase shiftSo far I think it might be an issue with initial conditions on my transient simulation. but I'm not sureI attahced a screenshot below of the outputs. also attached the .asc file for both the .ac and .tran simulations

author: RFDx
author_rank: Regular Contributor
timestamp: November 07, 2024, 08:07:09 am
content: Are the motional inductance and resistance values real? These look rather large for a ~51k crystal.Q is very large, you will have no luck with a transient analysis. Doing an AC sweep is the way to go. Below is what I got after getting the total phase shift to 180° by raising R2=220k and C4=68p and loading the output with 10 MOhm.For comparison a single transistor 32.75kHz Pierce crystal oscillator is shown. Loop gain and phase shift is included. Crystal dissipation is kept below 1uW with the help of a diode limiter.

author: iMo
author_rank: Super Contributor
timestamp: November 07, 2024, 08:16:41 am
content: I would recommend you to use the "new" .FRA analysis when using transistors/opamps or any active components.It makes gain and phase graph but differently to the .AC, as the .AC analysis first decompose the schematics into a simplified model ("small signal" model without active parts)..FRA uses original schematics unmodified.PS: OP - plz do label the wires with "names" so we may see what/where you are measuring - see below..
LTSpice design - Page 1
Forum section: electronics / projects

author: J4e8a16n
author_rank: Regular Contributor
timestamp: April 14, 2014, 02:32:06 pm
content: How can I create a back EMF simulation of a motor in LTSpice?It is a 1.5 volt toy motor.Rename the file to BackEMF.asc to use itJP

author: dannyf
author_rank: Super Contributor
timestamp: April 15, 2014, 06:04:23 am
content: Yes, if you can articulate the mechanism of back emf.

author: J4e8a16n
author_rank: Regular Contributor
timestamp: April 15, 2014, 03:05:45 pm
content: Here is a trial.

author: J4e8a16n
author_rank: Regular Contributor
timestamp: April 15, 2014, 03:07:10 pm
content: Here is the asc file

author: codeboy2k
author_rank: Super Contributor
timestamp: April 19, 2014, 12:31:00 pm
content: I have the following lying about, I found it online a while back from the University of Colorado Electrical Engineering course ECEN2830. You might find it useful to you.There are two .asc files in the zip file (1) DC_motor_model.asc and (2) DC_motor_model_test.ascThe motor model includes the back emf and the current changes as the load changes. There is an input that you can use to control the load.. The test file uses a PWL current sink at the load control input (omega) to apply varying loads. The test file applies the voltage step to turn on the motor, and then turns it off, at which point you can see the current draw and the back EMF at the motor's +DC input terminal. The model accurately depicts the current changes due to load changes as well.There is also a PWM motor speed encoder output.

author: J4e8a16n
author_rank: Regular Contributor
timestamp: April 19, 2014, 04:11:24 pm
content: Thank you so much.JP
LTSpice export data as txt, reducing number of points - Page 1
Forum section: electronics / projects

author: Cloud
author_rank: Regular Contributor
timestamp: January 18, 2022, 07:33:28 pm
content: So for dissertation I need a few plots from different programs which I hate so I have created python script to create plots from csv files. Now the problem is with LTSpice file which is 1.8GB. Is there a way that I can export every 10th or 100th point?

author: ledtester
author_rank: Super Contributor
timestamp: January 18, 2022, 08:29:01 pm
content: After exporting the plot data as a txt file you can use a variety of text processing tools to extract every n-th line.Using Unix utilities (which are available under Windows with WSL):https://unix.stackexchange.com/questions/369181/printing-every-nth-line-out-of-a-large-file-into-a-new-fileand here is a streaming solution with Python:https://stackoverflow.com/a/51744520/866915

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 18, 2022, 08:41:53 pm
content: I suppose the OP would like to find a way for LTSpice to generate smaller files, to avoid having to store, and handle large text files to begin with. The rest, they can probably do it?LTSpice can export plots to "text" files - those are actually CSV, with the separator being a TAB character.Unfortunately, I don't think there is any setting for this. Even the format itself (including the separator) is not modifiable.An alternative would be to read the RAW files directly, instead of exporting plots to text as an intermediate. I believe there are libraries for reading those RAW files.Take a look at this:https://www.nunobrum.com/pyspicer.html

author: Cloud
author_rank: Regular Contributor
timestamp: January 23, 2022, 07:34:05 pm
content: I have found out that files are not the same size for different C size in simulation. So I am thinking one option would be to separate txt file into separate runs (or just run fixed simulations instead of step) and than create a python script to reduce number of lines in each txt file so all files will have same number of lines

author: ledtester
author_rank: Super Contributor
timestamp: January 23, 2022, 07:57:00 pm
content: Note that it's possible that the time coordinates in the files won't be the same between simulations:https://groups.io/g/LTspice/topic/50218484so I imagine you'll want the python scripts to do some interpolating so all of the data has a uniform time base.

author: Cloud
author_rank: Regular Contributor
timestamp: January 30, 2022, 08:22:18 pm
content: Probably I will just run single simulation for every value C and then plot every run separately into same plot. That way I believe everything will be correctly aligned.
LTSpice files for third party components - Page 1
Forum section: electronics / projects

author: garvind25
author_rank: Regular Contributor
timestamp: June 01, 2025, 02:11:39 am
content: Hi,Just wanted to check if anyone knows any site for downloading the LTSpice files for third party components pls? I am looking for the .sub and .asy files of TLV272 and TL07x. Could not find the same in TI website.Thanks,Arvind Gupta

author: incf
author_rank: Frequent Contributor
timestamp: June 01, 2025, 02:16:36 am
content: ltspice wiki may have itI believe there used to be a yahoo group (or something like that) with a bunch of files that are now lostthere may be some git repos

author: moffy
author_rank: Super Contributor
timestamp: June 01, 2025, 03:13:20 am
content: Quote from: garvind25 on June 01, 2025, 02:11:39 amOnsemi have a SPICE model for the TLV272, rename the extension to .sub.
LTSpice freezing often - Page 1
Forum section: electronics / projects

author: atferrari
author_rank: Frequent Contributor
timestamp: February 03, 2015, 01:00:38 pm
content: I have been using intensively LTSpice in the last week always in the same PC. I find that when I change the circuit configuration adding / deleting a connection or components and ask for a new run, I have high chances that it will freeze in the first steps.After many failures I found that clicking on the "save" icon, prior clicking on "Run", the freezing is almost not happening again. Is it any possible setting that I could have wrong? I discarded everyghing related to time step because the circuits involve more or less similar components and basically change little by little, and, after saving, it starts and simulates normally.Comments appreciated.

author: AndyC_772
author_rank: Super Contributor
timestamp: February 03, 2015, 01:16:13 pm
content: I can't say I've experienced this behaviour. Which OS are you running? Are you saving your schematic to a local or to a network drive?

author: atferrari
author_rank: Frequent Contributor
timestamp: February 03, 2015, 02:38:28 pm
content: Win XP.The .asc files are all inside\LTC\LTspiceIVin the PC.

author: dannyf
author_rank: Super Contributor
timestamp: February 03, 2015, 03:28:40 pm
content: I have experienced it on a win7 machine -> it seems to be waiting to write to a file for 10 seconds or so and then everything goes fine after that.

author: atferrari
author_rank: Frequent Contributor
timestamp: February 03, 2015, 09:09:32 pm
content: Quote from: dannyf on February 03, 2015, 03:28:40 pmIf I wait enough, I eventually could see a notice popping up saying that an serious error occurred and that info would be sent to Microsoft, and that I will loose my work. Anyway, it saves everything prior starting...and freezing. Basically annoying.
LTspice: Issues with grounds (TPSI31P1-Q1) - Page 1
Forum section: electronics / projects

author: Alaezae
author_rank: Contributor
timestamp: September 22, 2025, 10:57:38 pm
content: I am trying to simulate a TI part that I want to use for a contactor precharge circuit. The TPSI31P1-Q1 is an isolated precharge driver that builds up charge on the DC link capacitor with a FET. The spice model from TI didn't end up working out (so many errors that I just gave up on it), but I created my own model of the part using some standard LTspice primitives. I then built the circuit I plan to use as the cap charger around the model (see the first image). This follows the example set by the evaluation board that TI sells for this part (see second image).I am having trouble when I add the main battery into the circuit. I can connect the 565V source to the power ground (equivalent to VSSS on the TI part and the LTspice GND net) to see a switching waveform. It does almost exactly what I would expect it to, rising to 1.2V before shutting itself off (the same on the falling side). That being said, the Vout+ voltage is negative, not slowly climbing towards the supply. See the third image.Notice that from the evaluation configuration, the reference of the 565V supply should be connected to the other side of the DC link capacitor. When I do this, however, the voltage does not rise on the output. The whole circuit stops working and the sense line stays essentially at 0V. I have tried connecting these with different points where the power ground is labeled PGND and the actual ground is on the 565V source. Same problem. It seems that any time the return line on the 565V source is connected to the link cap, this phenomenon occurs.Any thoughts? Seems like I have the ground connected incorrectly somewhere, but I'm not sure where to fix it...

author: iMo
author_rank: Super Contributor
timestamp: September 25, 2025, 11:14:41 am
content: ..do always post your .asc file when looking for an advice..
LTspice Lesson 3: Transmission lines part 1 - Page 1
Forum section: electronics / projects

author: Kashif
author_rank: Contributor
timestamp: August 30, 2019, 07:52:12 pm
content: Here is the third installment of LTspice Lesson focus on simulating transmission line, if interested in this topic, please check it out!In this lesson we will focus on single element Lossless Transmission line (T-line) as shown in Figure 1. Lossless T line simulation will be introduced here. One of the goal of these lessons are to give out practical examples from real world. Transmission line model real world signals very well. This lesson focus on the Lossless T-line where no power gets dissipated during transmission. In a future lesson, we will focus on lossy line and loss mechanics.What is transmission line? A transmission line is any conductor along with a return path where a signal travel from source to load. Because of finite speed of light, a signal takes a finite amount of time called Time Delay (TD) to go from source to load. Signal sees a characteristic impedance (Zo) based on geometry and dielectric around the conductor and return path. For an in-depth review of transmission line, please refer some excellent references as given at the end.In any simulation we need to build confidence on the models given. One way to do this is find solution of easy problems by hand for cases a formula or numerical values can be derived and then compare them with results from simulation. Once 100% agreement is established, one can go beyond simple situation and start modeling real world effects. In the case of transmission line, let’s look at 4 simple but common cases, where a 50Ω T-line is driven by a CMOS driver with 5Ω source impedance (typical for newer drivers) with an open load, short load, 100Ω load and a properly terminated 50Ω load.For each case, we will look at the load voltage waveform using bounce diagram. If you haven’t learned or played with bounce diagrams, do not fret, we will walk through it step by step.Continue here:https://iexploresiliconvalley.com/2019/08/27/ltspice-lesson-3-transmission-lines-part-1/
LTspice Lesson 5: How to simulate impedances?  - Page 1
Forum section: electronics / projects

author: Kashif
author_rank: Contributor
timestamp: July 12, 2020, 03:54:29 am
content: All,Continuing my lessons: LTspice Lesson 5: How to simulate impedances?LTspice Lesson 5: How to simulate impedances?Posted on July 11, 2020 by ExploreSiliconCommands covered: .ac .measWhat is impedance? Impedance is simply defined as voltage divided by current (Z = V/I). This definition of impedance applies to both in the time domain or the frequency domain. In the frequency domain it’s really the magnitude and phase of sine wave that are used for voltage and current. The math involve complex algebra, but doable for simple circuits. This is really the basis to do simulation in LTspice.V = Z * IChoose I=1A constant current source, then V = Z. We can measure voltage easily in LTspice that essentially equal to impedance. Let’s illustrate how this work in LTspice using basic passive components.Figure 1: Simulation circuit for a resistor, a capacitor and an inductorcontinue here...https://iexploresiliconvalley.com/2020/07/11/ltspice-lesson-5-how-to-simulate-impedances/Enjoy and feel free to comment and provide any suggestion here.Link to all the lessons so far:https://iexploresiliconvalley.com/category/ltspice-for-ee-students/

author: Hawkansson
author_rank: Newbie
timestamp: January 21, 2022, 07:27:49 am
content: Dear Kashif, I came here on a somewhat different, but related question. I am looking to simulate a measured impedance in ltspice. Do you know if there is any component in ltspice that allows custom impedance data, like "Freq, Mag, Phase" csv format for instance?Best regards,David

author: Kashif
author_rank: Contributor
timestamp: December 06, 2022, 12:50:55 am
content: Hi David,Sorry missed your message, do you mean how to import measured impedance data in CSV format into LTspice? If that is case, I am not aware of easy way of doing it. If purpose is to do some comparison between measurement and simulation, I would export LTspice simulation data and do a comparison in some other tools like Python or Matlab. Hope this help!BR,Kashif
LTSPICE Looking for someone to bring this PCB/schematic into LTspice for simulat - Page 1
Forum section: electronics / projects

author: pulsed_power
author_rank: Frequent Contributor
timestamp: June 05, 2024, 05:43:20 pm
content: Are there any LTspice experts available?I AM NOT LOOKING FOR THIS WORK TO BE DONE FOR FREE. JUST A REASONABLE PRICE.LOOKING FOR SOMEONE TO BRING THIS PCB/SCHEMATIC INTO LTSPICE FOR SIMULATION.

author: DimitriP
author_rank: Super Contributor
timestamp: June 05, 2024, 06:17:41 pm
content: What you have here is unsimulatable (if thats a word).Missing component values to start with.And the way you are presenting it, its's more of a "reverse engineer" from the PCB layout project rather than "schematic to LTSPICE" project.and with missing component values and semiconductor types simulation becomes... "problematic"If you can't find an exctual circuit diagram at least let us know what the "thing" is since manufacturers sometimes have similar versions of their circuits in use in other models.So add more info to make the projecta) Do-ableb) more reasonable in pricec) end up with something usable to simulateIf I'm wrong on any other above I'm sure I'll be corrected soon enough
LTSpice - multiple simulations - Page 1
Forum section: electronics / projects

author: tree
author_rank: Regular Contributor
timestamp: January 03, 2014, 02:18:02 am
content: Hello all,I was wondering if it's at all possible to run multiple simulations in LTSpice (e.g. DC Operating Point and Transient) without changing the simulation condition or commenting one out, i.e., is it possible to get two analyses from clicking on 'Run' once by having one statement but it contains instructions to run two types of simulations.Thanks.

author: tree
author_rank: Regular Contributor
timestamp: January 04, 2014, 01:28:13 am
content: BUMP

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: January 04, 2014, 02:42:21 pm
content: Hi,As far as I know you can not run multiple types of simulations from a single 'Run'. The reason for my thinking is that LTspice would not know which data to display if you clicked on a point.You can do the following:You can display the operating point when doing an AC analysis:The way to do this is:Right click on blank are on the schematic.A box will open select 'View'Make sure that the box 'Show .op data flags' is checkedLeft click on 'place .op data label'. Place the data label on the node that you want to observe.Every time you run the simulation the '.op data flags' will be updated. Try changing the voltage V1 and run the model you will see the operating point update.I have attached a zip with the model.This also work in the time domain. I have modified the model to add a second source. Note: one of the simulation commands is now a comment.I have also attached a zip file with this model.Jay_Diddy_B

author: tree
author_rank: Regular Contributor
timestamp: January 04, 2014, 04:48:25 pm
content: Thanks Jay,All you had to say is "LTSpice can't". But I really appreciate you going out of your way to show how one combination CAN be done.In response to your statement that LTSpice wouldn't know which plot to show:That shouldn't be that difficult to add. The software would just have to change the netlist with the different type of simulation conditions and generate two SEPARATE PLOT PANES.

author: Unknown
author_rank: Unknown
timestamp: January 04, 2014, 04:50:17 pm
content: Can you not run 2 instances of LTSpice?

author: tree
author_rank: Regular Contributor
timestamp: January 04, 2014, 06:03:19 pm
content: Quote from: Lurch on January 04, 2014, 04:50:17 pmI can. But that requires more work than having two simulation statements.