hybridfree/eevblog-posts huggingface dataset:
matte tin pin contact with ENIG PCB - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 01, 2019, 03:45:17 am
content: Good day!Samtec OPP connectorhttp://suddendocs.samtec.com/catalog_english/opp.pdfAs you can see these are spring-formed matte-tin-plated pins that mate to a pad on another PCB.They say it should mate to a tin-plated pad.Page 3:http://suddendocs.samtec.com/prints/opp-xx-01-x-s-x-xx-footprint.pdfSo what happens if the pad is ENIG instead? Will the Sun go red giant? Will Jupiter turn into a quasar?Will there be some kind of tin-gold intermetallic shenanigans ??Samtec says this is "not recommended" and won't tell me more than that. Unfortunately the mating board is already done, it's ENIG.

author: wraper
author_rank: Unknown
timestamp: November 01, 2019, 04:54:45 am
content: Likely you will start having contact failures after few months to years.QuoteThen tin the pads and thoroughly clean from flux. Although I don't advise using connectors of such style (springy) in non gold plated variants. If you want to go with tin, use connectors which strongly bite into solder on the pad. Such as commonly used in HDDs.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: November 01, 2019, 11:36:01 am
content: Yeah this connector wasn't my choice, I did leave paste on the mating pads and when the boards got assembled I got an earful when my boss saw the solder.I guess it's a wait and see thing now...
MAX 7000S driving 5V Logic - Page 1
Forum section: electronics / projects

author: NivagSwerdna
author_rank: Super Contributor
timestamp: February 14, 2019, 11:48:29 am
content: In the context of 1980s Arcade game PCBs...I'm contemplating having a go at replacing some custom logic with a MAX 7000S device which appears to be pretty cheap on ebay (despite being obsolete). If I drive the device at 5V I see that in order to drive 5V CMOS outputs that an external pull-up resistor is required, I even found an application note:http://extras.springer.com/2001/978-3-662-04615-9/an/an107.pdfHow am I meant to calculate RExt? 10k 47k?EPM7128SLC84-15 is the device of choice.Thanks in advance,

author: edgaras006
author_rank: Contributor
timestamp: February 14, 2019, 12:58:45 pm
content: From load capacitance and required switching frequency. Since it uses only nMOS logic, for +5V output you need a pull up resistor. R = 1/(2*pi*Cload * F switching). On the other hand, RC should be approximately 1/10 of switching frequency. Side note if you reduce R too much you might hit n most current limit, so watch out for that.
Max LEDs powered via USB2? - Page 1
Forum section: electronics / projects

author: 3dgeo
author_rank: Frequent Contributor
timestamp: October 12, 2018, 05:35:49 pm
content: Hi,I'm making custom USB macro keyboard with around 40 keys and want to RGB it (48 RGB leds – 144 leds total).I need some help calculating current: lets say one >RGB< LED takes 0.056A@3V, so all 48 RGB will take ~2.7A, in total a bit over 8W, is my calculations OK so far?As to my knowledge USB2 can provide max 0.5A@5V, that is 2.5W.Obviously I need to multiplex them, currently my plan is to use 3 * TLC5940PW and control only 16 RGB LEDs at one time.16LED * 0.056A * 3V = 2.7W – still too much power, but I can lower each LED current with TLC5940PW resistor, cos I thing I'll have enough brightness even while multiplexing? Is my approach optimal or is there a better way to do what I want?Other thing I try to figure out: I need 3 PNP transistors for multiplexing as well, is there a reason why I shouldn't use these mosfets?https://www.vishay.com/docs/70833/70833.pdf(I'll make proper PCB)LEDs I'm planning to use:https://www.aliexpress.com/item/Hot-sale-3mm-RGB-led-diffused-4-PIN-multicolor-dip-led-2-6-3-5-6/32680356046.html?spm=a2g0s.13010208.99999999.265.3f8e3c00HVfABvThank You for Your time.
Max real-world operating temperature for a monolithic DFN switching power IC - Page 1
Forum section: electronics / projects

author: Psi
author_rank: Super Contributor
timestamp: January 01, 2021, 02:25:27 am
content: I'm designing a switching power supply (battery charger) using LTC4162-Shttps://www.analog.com/media/en/technical-documentation/data-sheets/LTC4162-S.pdfThe absolute max junction temp from DS is 125C which is obviously way to hot for actual operation.I'm trying to come up with a max operating temp that would be reliable for the intended application.Then I can consider the ambient temp in the hottest expected environments and decide if my heatsinking is adequate.The product will never be active 24/7 or anything near that. It will be active for between 30min to 2 hours and the time to next usage is probably over a week. (It's not a device that get used often).So it can probably run a bit hotter than a system that needs to run 24/7.My thinking is that it should be under 85C in all cases to be safe.The chip has thermal limiting that kicks in at 120C, but I don't ever want that to trip except it a gross fault scenario. (This limit can be adjusted over I2C and I might do that in a future version that has a MCU, but this one does not)Computer CPUs thermal throttle at ~100C and it's pretty uncommon for CPUs to fail.Considering how normal it is for some laptops to sit on thermal throttle limit under heavy use you'd have to think that 100C can't be that bad.There's also that piece of test gear Dave reviewed ages ago with a VReg that was running at 100C as standard.Does anyone have any comments?

author: Psi
author_rank: Super Contributor
timestamp: January 01, 2021, 11:45:22 am
content: Interesting.I would have thought any standard PCB would handle chip temps up to 100C.Maybe I should spec the PCB to be TG 150-160 instead of TG 130-140.It's not a huge amount more cost.

author: Psi
author_rank: Super Contributor
timestamp: January 01, 2021, 12:01:19 pm
content: Quote from: blueskull on January 01, 2021, 11:55:53 amTrue, but DFN are pretty tiny vs even a midsized BGA.So the expansion difference over the width of the package is much smaller.
MAX038 function Gen. Dave's old EA 1996 design. EL2001 substitute, MAX4213? - Page 1
Forum section: electronics / projects

author: wilfred
author_rank: Super Contributor
timestamp: June 24, 2018, 12:39:51 pm
content: I have just acquired a few MAX038's and I want to build it into a function generator like the one Dave published last century. This is a link to the circuit.http://alternatezone.com/electronics/images/hsfglc11.gifAnd this is a link to his old website with a copy of the article.http://alternatezone.com/electronics/hsfg.htmThe question I have relates to this paragraph."The MAX038 contains it's own low impedance output buffer, but this is of nouse if the final output level needs to be varied, in this case by VR2. Thewiper of VR2 is fed to the final stage buffer chip IC3, an EL2001manufactured by Elantec. The EL2001 is a 70MHz fixed unity gain buffercapable of driving 50ê coaxial lines. R17 provides close to a standard 50êoutput impedance."The EL2001 is long obsolete (like the MAX038) but I can get a EL2002, maybe, for $20. Which I'd rather not. Correct me if I am wrong but I am thinking the EL2002 is just a higher frequency version of the EL2001. I am no design engineer.Since I am no design engineer I want to ask what it is about the EL2001 that made it so suitable for driving a 50ohm output? I am thinking it is the 100mA output current capability. Because the MAX038 is also so old I don't seem to find other designs that use cheap and/or easily available chips.Anyway after a bit of searching around I came across the MAX4213 which also specifies a 100mA output drive current and conveniently page 1 of the datasheet includes a typical application of a unity gain buffer driving a 50Ohm load. Serendipity or what?So, to get to the point, would the MAX4213 be a suitable substitute for the EL2001 in this application? Or what would be another choice.EL2001 datasheet pdf link.https://4donline.ihs.com/images/VipMasterIC/IC/INSL/INSLS05194/INSLS05194-1.pdf?hkey=EF798316E3902B6ED9A73243A3159BB0MAX4213 datasheet link.http://www.farnell.com/datasheets/32471.pdf

author: EEVblog
author_rank: Unknown
timestamp: June 24, 2018, 12:56:31 pm
content: Quote from: wilfred on June 24, 2018, 12:39:51 pmI thought you were exaggerating, so I checked, Aug 1996 issue of Electronics Australia, damn, yep, last century

author: EEVblog
author_rank: Unknown
timestamp: June 24, 2018, 01:08:12 pm
content: Quote from: wilfred on June 24, 2018, 12:39:51 pmYes, the high output current, plus unity gain stable (obviously being a purpose designed buffer)QuoteYep, should work fine.
MAX038 pspice Library help - Page 1
Forum section: electronics / projects

author: igorbog
author_rank: Contributor
timestamp: March 31, 2012, 10:32:40 am
content: Hi.Where I can find max038 pspice model? Is there any other way to simulate it?

author: amspire
author_rank: Super Contributor
timestamp: April 01, 2012, 11:15:53 am
content: The MAX038 is a waveform generator. It is a complex function IC and Spice simulations of complex function IC's are usually not great, unless someone has done a brilliant job with the model.Why do you want to simulate it?Richard.
MAX11600 ADC frontend - buffering required? - Page 1
Forum section: electronics / projects

author: cio74
author_rank: Regular Contributor
timestamp: February 06, 2018, 08:03:00 am
content: Hello,I have some devices located about 100 meters away and I want to know if they have been disconnected or not. Wire can be damaged and the idea is to use an ADC and a voltage divider to have a known state - default - voltage when the cable is good and contact is closed. Besides contact open I would know if the wire got damaged. It is quite popular in the automotive industry where they like to monitor wiring status besides contact status.I was thinking to use one of Maxim's MAX11600 ADC series chip but it's probably valid for any other ADC. Single ended, single supply. Those Maxim chips feature internal diodes to Vdd and GND. Their MAX11613EVSYS+ evaluation kit has the schematics and its only a RC filter at each input.It is a light industrial environment, do I need any sort of buffering/amplifying, OP amp, or it's just good without it.Thanks.

author: danadak
author_rank: Super Contributor
timestamp: February 07, 2018, 02:25:21 am
content: Many approaches.What is cabling, coax, shielded, simple twisted pair.....? Line carrying analogsignal or digital ?You could use a TDR approach, that would find actual location of fault, if any.Or constant current driving the line and sampling V.Or measuring line C.......Regards, Dana.

author: cio74
author_rank: Regular Contributor
timestamp: February 08, 2018, 09:30:16 am
content: Quote from: danadak on February 07, 2018, 02:25:21 amIt is just simple a twisted pair wire.A basic design like two resistor to make a voltage divider, one resistor at the PCB side and the other at the contact side. Then via a RC filter going into the ADC.
MAX14870 Motor Driver Current Sense Resistor Confusion  - Page 1
Forum section: electronics / projects

author: techy101
author_rank: Unknown
timestamp: September 27, 2016, 06:44:40 pm
content: I'm working with a Maxim MAX14870 (Datasheet) brushed DC motor driver and am having a difficult time understanding the selection of a current sense resistor. The goal is to measure motor current as a way to determine torque. My motor voltage is 6V I am not utilizing internal current regulation, so I have the SNS pin tied directly to ground (as mentioned on page 13).The datasheet says the following regarding current sensing:QuoteI'm unclear how to calculate the RSENSE value because I'm not clear on what VCOM ends up being?I feel like this should be a very simple thing, but I'm stuck... Any guidance would be appreciated.Thank you,Matthew

author: H.O
author_rank: Frequent Contributor
timestamp: September 27, 2016, 07:57:58 pm
content: The way I understand is it that VCOM would be the voltage at the COM terminal at any given motor current and the VCOM can't be allowed to swing more than 250mV above or below GND.So if your motor is pulling a maximum of 500mA then RSENSE must be 0.5ohm or smaller as to not create a voltage at COM of more than 250mV.
MAX17055 fuelgauge. Any experience? - Page 1
Forum section: electronics / projects

author: plazma
author_rank: Frequent Contributor
timestamp: February 12, 2018, 04:34:44 pm
content: I have worked with products with TI coulomb counter fuelgauges and software fuelgauge based on characterization tables. The SW based worked better than the TI chip.A newsletter caught my attention to Maxim MAX17055 fuelgaugehttps://www.maximintegrated.com/en/products/power/battery-management/MAX17055.htmlDoes anyone have experience with this?Looks interesting though we have bad experience with Maxim chip availability.

author: twospoons
author_rank: Frequent Contributor
timestamp: February 10, 2019, 10:27:36 pm
content: I know its a long time since the OP, but ..I've been using the MAX17055 in a product, and the result has not been as good as promised by the marketing hoopla. Mostly I find the chip reports remaining charge to be far less than reality, meaning it reports "empty" far too soon.Maybe its the Panasonic NCR li-Ion batteries I'm using, maybe its my application (lots of deep sleep, with short bursts of high current activity), maybe I've screwed up a register setting. Or maybe the chip doesn't work as advertised.I'm still hunting for an answer - Maxim tech support had nothing useful to offer.

author: wobblywobble
author_rank: Newbie
timestamp: April 24, 2025, 12:23:00 pm
content: Quote from: twospoons on February 10, 2019, 10:27:36 pmI know that a lot of time has passed, but I am curious if you have managed to resolve your issues with the MAX17055. The project I'm working on has similar application to the fuel gauge to your example. I would be very grateful if you could share some hands-on insight on the topic.
MAX17320 fuel gauge going into permanent fault upon restart - Page 1
Forum section: electronics / projects

author: roli
author_rank: Regular Contributor
timestamp: December 23, 2021, 07:01:44 pm
content: Hi!I've been trying to create a new battery pack for an old (and long discontinued) Sony product. Luckily the battery pack in question uses standard smart battery specification. So I've designed a new PCB and instead of using the old fuel gauge/protector combo I've gone and used modern Maxim MAX17320 fuel gauge/protector IC. And here is where I am having some trouble...Upon connecting a 2 cell RC battery to it (for testing purposes) and shorting the discharge/charge pin to the battery positive terminal (to wake the IC up) the IC starts communicating with the MAX17320 programming software. Problem is that immediately upon starting it goes into permanent failure mode. The below two screenshots:Upon clearing the PermFail flag the FET failure indicators turn green and the pack starts working as expected. My initial thought was that this was due to the parameters being wrong so I went through configuration wizard (hopefully setting up everything correctly) and writing the configuration to RAM. But again upon doing so and rebooting the IC goes into PermFail mode...Since clearing the fault works - the battery behaves as expected based on a short test in the actual product - I tried to write the working configuration into non volatile memory. But I can't do so because the software complains that I need to fix the permanent failure first. Any ideas on what I am doing wrong? Why is it going into pfail in the first place? The status bits don't seem all that helpful.Some additional info: I am not using any permanent protections on the PCB - so I have the PFAIL output connected to ground with 1k resistor as described in the datasheet. When going through the programming wizard I also disabled permanent failure protection and unchecked the option for disabling programming in case of permanent failure. But that doesn't seem to do anything.Schematic for my board is here... it's mostly based on the evaluation board:Link to datasheet:https://datasheets.maximintegrated.com/en/ds/MAX17320.pdfSome helpful person on another side suggested that I try scoping out the gate pins for the MOSFETs, which I did... The Q1 seems a bit weird. When powering on the module (and it goes into fault mode) the gate pin is at about 7V (meanwhile the Q2 gate pin is at around 500mV). When clearing the fault both gate voltages rise to around 14V. I don't really have a good understanding of how this is supposed to work, but those 7V in permanent fault mode seem wrong.
MAX17710 Charger and recommended battery - Page 1
Forum section: electronics / projects

author: Goature
author_rank: Contributor
timestamp: February 02, 2016, 10:41:33 am
content: Hello all!I'm having fun with the MAX17710 Energy-Harvesting Charger and Protector. The IC is designed to charge a 4.1V rechargeable cell, and the datasheet specifies the Thinergy MEC200-series as a suggested battery. I have not been able to find this battery for sale, at any of the common distributors. Do you have any suggestions to what replacement I can use?Ps. The datasheet specifies that the cell has to be a "low-capacity cell", but that doesn't tell me much. Im therefore not sure, if a single cell LiPo will be too large. The Thinergy Batteries are <3mAh.Tinergy MEC201:4.1V1mAh350uA discharge30mA Max discharge1"x1"x0.01"

author: Goature
author_rank: Contributor
timestamp: February 03, 2016, 08:22:09 am
content: For anyone interessted, I managed to find the following:EFL700A39 from STMicroelectronics (0.7mAh)PGEB201212 from PowerStream (10mAh)CBC050-M8C from Cymbet (5uAh)

author: amyk
author_rank: Super Contributor
timestamp: February 03, 2016, 11:59:06 am
content: According to the datasheet, this charger charges at625nA, or 0.625uA. That is atinyamount of current. At that rate, even a 5uAh cell will take 8 hours to charge. I doubt a larger cell would even charge, because its self-discharge will far exceed that. For comparison, the protection circuitry of a regular lion cell continually draws a few uA, which is several times more than the charge current this IC can put out.To give a perspective on the order of magnitude, a typical 18650 of ~2000mAh capacity would theoretically, ignoring leakage and other losses, take over 365yearsto charge at that current.

author: Goature
author_rank: Contributor
timestamp: February 03, 2016, 08:57:11 pm
content: Quote from: amyk on February 03, 2016, 11:59:06 amIt might be me that is misunderstanding, but the value you are referring to is the quiescent current (I_qchg) of the charger when active. Some might call this value the "leakage current". The charger actually has a typical charging current rated to 100mA (CHG Maximum Input Current). Limited by other maximum ratings of course.Can anyone confirm this?

author: sleemanj
author_rank: Super Contributor
timestamp: February 03, 2016, 10:02:19 pm
content: Quote from: Goature on February 03, 2016, 08:57:11 pmI concur,CHG Continuous Current(limited by power dissipation of package) ...................100mACHG Quiescent Current IQCHG VCHG = 4.0V rising, VBATT = 4.0V 625 1300 nA
MAX17783 DC-DC Converter - Adjusting Output Voltage  - Page 1
Forum section: electronics / projects

author: Franc
author_rank: Regular Contributor
timestamp: September 08, 2025, 11:44:19 pm
content: hello friend, how are you!!I´m trying to understand how Vout in MAX17783 was calculated. I will be greatful for any help.In datasheet page 15, we can see this formula attached forRtopandRbot.When we check the circuit application for Vout 5V (page 18) we find 221K forR3and 48.7K forR4but when I used that formula of page 15 I cant find these values.Im using these values for calculating :Fc = 62500 (1/8 of 500kHz)Cout_Sel = 18uF (value found in Cout formula)I checked out about DC Bias of capacitor 22uF that Analog using in Datasheet (GRM32ER71C226KEA8) and I can see the Bias DC for 5Vcc is ok, around 19uF as we can see in picture attached.Question is.... What Im doing wrong? Im finding 192K for R3 and they are using 221K.Thanks a lot!!

author: OhmBob
author_rank: Newbie
timestamp: September 09, 2025, 01:13:01 am
content: ou’ve correctly identified the challenge. The formula on page 15 of the datasheet is a general one for setting the output voltage, but the application circuit on page 18 uses specific, slightly non-standard values (221kΩ and 48.7kΩ) to achieve a 5V output for a very important reason: compensating for the DC bias effect of the output capacitor.You are not doing anything wrong in the basic calculation. Using the standard formula:VOUT=0.6V×(1+RTOPRBOT)VOUT​=0.6V×(1+RBOT​RTOP​​)Plugging in the values from the app circuit:5V=0.6V×(1+221kΩ48.7kΩ)5V=0.6V×(1+48.7kΩ221kΩ​)5V=0.6V×(1+4.538)5V=0.6V×(1+4.538)5V=0.6V×5.5385V=0.6V×5.5385V≈3.323V5V≈3.323V

author: Franc
author_rank: Regular Contributor
timestamp: September 09, 2025, 01:24:43 am
content: Dear Bob, thanks a lotI can read your formula above.Where did you find this formula? Could you explain more this Vout = 0.6V?Regards!!
MAX1873 Charging IC - Please Help - Page 1
Forum section: electronics / projects

author: lucent567
author_rank: Newbie
timestamp: August 07, 2016, 12:48:02 pm
content: Hello,I've designed a circuit based on the MAX1873:https://datasheets.maximintegrated.com/en/ds/MAX1873.pdf(I've also attached the application design from the datasheet and the application design of the evaluation board)I need to charge 4 cell Li-Polymer batteries (connected in series).The max voltage of each cell is 4.2V so I set the charging target voltage to be 16.4V which is 4.1V per cell (just below the maximum).Also, I don't need the input current monitoring feature so I shorted the pins CSSP and CSSN to DCIN as written in the datasheet:"Short CSSP and CSSN to DCIN if the input-source current-limit feature is not used".I chose CBATT to be 33uF as indicated on page 8.ICH/EN is connected to VREF via a 10K ohm resistor.I used a resistor of 0.07ohm for RCSB to get a charging current of around 2.8A.However, now that everything is soldered and all I get a constant charging current of 70mA. This might be OK if the battery pack voltage is close to 16.4V but that is not the case. The voltage is at around 15V so this does not make sense.I was wondering if anybody had any clues as to what could be wrong in my design?Please take a look at my design attached.Thanks,David

author: Ton
author_rank: Regular Contributor
timestamp: August 09, 2016, 06:49:15 pm
content: I will give it a goand welcome to the forum.I cant find a input capacitor, the sample board have a 47uF (low esr) at the source of Q2, without a local input capp, the current pulses have to come all the way from your power supply. creating switching noise and voltage drop all the way.If you can show us the layout or some detailed pictures of the circuit we might be able to give more advice.In my experience then this kind of missing output current quite often is due to noise in the current sense circuit, due to parasitic capacitance and inductance, depending on layout, the typical culprit is switching noise from the node of Q2 drain / D2 / L1, adding a RC snubber here (parallel to D2) might help.Cbatt should be low esr and close to the coil and sense resistor to minimise the loop area.If you have access to a oscilloscope try to take a few measurements of the converter waveforms, this will give us some clues as to where to look further.interesting waveforms areswitching nodeCSBVbatVin....Br Ton
MAX1968 5.5V  +/- 3A TEC controller, unstable - Page 1
Forum section: electronics / projects

author: helge
author_rank: Regular Contributor
timestamp: October 19, 2014, 10:38:27 am
content: Yesterday I built a few test boards featuring the MAX1968 TEC controller (see picture). It may have been the leaded but non-inductive 0.1R shunt resistor that I soldered to the board (in a second and also failed attempt I replaced it with a 0.05R one) or the lack of a small cap over the current sense terminals but that bloody chip just was unstable (creating audible noise) and destroyed itself after some time.It appears that some of the internal switches got damaged during start-up or normal operation. But why? Is there a fundamental flaw in the layout?Here are my test scenarios:2x 22µH 3A inductors, 0.1R shunt resistor (current limited to +/- 1.5A)supply: 5.5Vswitching frequency: 500kHzpeltier device: 12V 6A cheap chinese peltier labeled "TEC1-12706" mounted to a CPU heat sinkpower-up with peltier, setpoint voltage = internal reference (no nominal peltier current)observations: current draw with and without peltier is around 0.02A and subsequently +/- 1.2A can be reached by attaching a trimmer to the supply rails and the control voltage input.After playing around with it, mostly to test whether different compensation caps and more output capacitance across the peltier would eliminate instabilities a standby current draw of ~0.3A appeared no matter whether the peltier was attached or not.And it got worse: the minimum peltier current setpoint shifted away from the 1.5V of the reference to 1.688V, indicating internal damage.Different setup: 4.7µH 6A, 0.1Rafter power-up, current consumption was found to be ~0.1A, changing from positive to negative peltier currents again exposed some audible instabilities. That test ended up in a fried MAX1968 drawing ~0.8A even without a peltier cooler attached (I should mention that voltage sensing and bypass caps ought have prevented excess voltage).So what have I learnt? I'm not sure. Unfortunately I wasn't serious enough about testing the board with the scope attached because.. well.. it's just a kind of dual synchronous buck converter with X7R caps close to everything and I expected it to work - or at least not destroy itself on power-up.The exposed pad TSSOP packages were soldered using a hot plate and hot air so I'm rather sure I wasn't too hard on them w.r.t. thermal gradients and heating / cooling rates. The layout is a bit strange, with the VDD polygon coming in from one side on the bottom layer but that's what you end up with when the power switch pins are scattered all over the package. I've filled all the vias with solder to minimize resistance.Maybe someone can enlighten me with what's wrong with this circuit.documents:datasheethttp://datasheets.maximintegrated.com/en/ds/MAX1968-MAX1969.pdfevaluation boardhttp://datasheets.maximintegrated.com/en/ds/MAX1968EVKIT.pdfreliability reporthttp://www.maximintegrated.com/en/reliability/maxim/MAX1968EUI.pdfedit: attached eagle .brd file
MAX22201 Motor Driver IC Enters Sleep Mode - Page 1
Forum section: electronics / projects

author: Cigarsnob
author_rank: Regular Contributor
timestamp: April 27, 2022, 10:25:27 pm
content: Hi Everyone,I designed a board with the MAX22201 to drive a motor and it seems to enter sleep mode when varying the frequency or duty cycle. Fault pin doesn't show a fault. Fault pin only shows a fault if I force on per datasheet, such as lowering VM from 12V to 2V.Anybody have experience with this chip?https://www.maximintegrated.com/en/products/power/motor-driver-ics/MAX22201.htmlI bought an eval board and it just arrived today. Hooked it up the same as in my system and vary the freq or duty cycle and the output turns off as well.Test Set Up:1. VM = 12V2. IN1 and IN2 connect to a function generator3. Function gen set to 22kHz with 80% duty cycle and CH2 has 180deg phase shift4. Resistor connected to output (normally I drive a motor)5. Oscilloscope current clamp measures load currentTest:1. Power on VM2. Turn on both IN1 and IN2 to wake IC3. Turn off IN14. Output current on scope looks as expected5. Vary either freq or duty cycle and output immediately turns off6. going back to step 2 above is required to wake IC up againUPDATE: Eval board has a PWM signal. I disconnected my function gen and used the on board PWM signal on one channel and grounded the other channel. I can vary the duty cycle with no issues now and the output stays on. My function gen is a Rigol DG4162. My guess which I don't fully understand is when I vary the duty cycle on the function gen, you need to click the align phase button. Possibly a function gen with this requirement is not best used for this application?

author: Benta
author_rank: Super Contributor
timestamp: April 27, 2022, 11:13:55 pm
content: 2. IN1 and IN2 connect to a function generator3. Function gen set to 22kHz with 80% duty cycle and CH2 has 180deg phase shiftHave you thought about the relationship between "80% duty cycle" and "180deg phase shift"?Seems to me to be a short-circuit.Try with 20...40% to start with.

author: Cigarsnob
author_rank: Regular Contributor
timestamp: April 27, 2022, 11:42:21 pm
content: Hi! Thank you for the comment.I've tried various duty cycles and got the same results
MAX232 BAKCKPOWERING RAIL - Page 1
Forum section: electronics / projects

author: jismal
author_rank: Contributor
timestamp: August 20, 2019, 07:10:28 am
content: Hello GuysDoes someone face issue of standard MAX232 driver back powering the power rail?Anyway, my IC was SP232. The issue comes as follows.#1 When I connect my RS232 ports to the device without powering the device on, The SP232 will not back power.#2 But when I remove the power of the device with RS232 still connected, the SP232 is back powering.#3 When I put a 100 ohm load on the back powering rail this back powering is turned off.# My RX voltage was around -5.85 Voltage and back powering rail was around 2.45 volt enough to power the led.
MAX3023 Level Translator - Page 1
Forum section: electronics / projects

author: andersendr
author_rank: Regular Contributor
timestamp: February 01, 2012, 11:50:12 pm
content: Hello Forum,I am bread boarding a MAX3023 Level Translator.http://datasheets.maxim-ic.com/en/ds/MAX13013-MAX3023.pdfI am having trouble with an extremely noisy signal on both the output and input. It is only during the high time. This only happens when I am translating from VL to VCC. When going from VCC to VL, all works fine. I am using the recommended 0.1uF decoupling caps. I am using a function gen to simulate input data. Anyone have any thoughts? Here are my specs below,VL = 1.4VVCC=3.3VFrequency 100HzMeasured Input Noise Amount 1.25VMeasured Output Noise Amount 1.25V***Edit***I noticed in the datasheet it says the input driver must have less than 25 ohms output impedance. Could that be a problem when driving them from the function gen.Also I tested it with a DC voltage and it works perfectly. 1.4V in and 3.38V out with no noise. So I need to determine a way to get rid of this noise.
Max3100 SPI UART Question - Page 1
Forum section: electronics / projects

author: docmur
author_rank: Regular Contributor
timestamp: March 19, 2015, 03:39:34 pm
content: Hey GuysHas anyone used this chip in the past? I've included this chip in my current design on a pic32mx360f256l micro-controller based system, as of yesterday it was mostly working, I could get my transmission from the micro-controller - over the spi, to the uart and see it on AccessPort.Without changing anything this morning I'm seeing just 0x00 over the UART and when I put break points in the program I'm seeing the wrong information come back from the chip. According to the datasheet, when I send data I should see something like:<R T 0 0> <0 RA/FE CTS PR> <DATA ONE> <DATA TWO>Come back over the SPI as a form of ACK, What I'm seeing is 0x4200 which means <DATA ONE> and <DATA TWO> are not being written to the chip correctly or returned and the 0x42 makes no sense as 2 would mean an invalid bit is set.When I break right after I configure the chip I see the right information come back, 0x600A, which is correct.Has anyone used this chip in the past and ran into these kind of issues.

author: docmur
author_rank: Regular Contributor
timestamp: March 19, 2015, 04:05:19 pm
content: WowFace palm moment of the day, I forgot to connect the clock. I swore I saw it connected but obviously not.Thanks anyway for anyone that took a look.
MAX31856 Thermocouple Amplifier Review - Page 1
Forum section: electronics / projects

author: girishv
author_rank: Regular Contributor
timestamp: December 01, 2022, 01:36:00 pm
content: Hi,I am using MAX31856 thermocouple amplifier for monitoring temperature in an industrial environment.Before posting here, I read various discussions on MAX31856 in the forum. There was a detailed discussion in the following thread.https://www.eevblog.com/forum/projects/max31856-thermocouple-amplifier/I am very thankful to all the people for sharing their knowledge and helping newbie's like me to avoid mistakes.I have created the following schematic based on above mentioned thread. What could I do to make this design immune to EMI?Girish

author: lasmux
author_rank: Regular Contributor
timestamp: December 01, 2022, 02:07:53 pm
content: Quote from: girishvYou should make sure that your 3.3V supply is clean (not from a switching regulator). You already have ferrites on the supply input, you could possibly increase C1 to >1uF. You have ferrites on the thermocouple inputs also, I'm not sure how this will affect the performance of the device but from the thread you linked it seems to not be a problem. You could possibly also add some series resistors (100 ohm or so) to the SPI port inputs/outputs to reduce switching noise/current draw.

author: girishv
author_rank: Regular Contributor
timestamp: December 01, 2022, 02:22:42 pm
content: Quote from: lasmux on December 01, 2022, 02:07:53 pmThanks for your inputs. I do have 150Ω resistors on SPI lines (based on evaluation boardMAX31856EVSYS#)

author: lasmux
author_rank: Regular Contributor
timestamp: December 01, 2022, 02:33:22 pm
content: That's great. I don't know how much experience you have with PCB design, but a lot of EMI reduction comes from the PCB layout. You should follow normal PCB design guidelines for reducing EMI and noise succeptibility: Make sure you have a continuous ground plane, that switching cuircuits and their return currents aren't going to be anywhere near the MAX31856 or sensor leads, that decoupling caps are physically near the IC, etc.

author: girishv
author_rank: Regular Contributor
timestamp: December 01, 2022, 03:35:11 pm
content: Quote from: lasmux on December 01, 2022, 02:33:22 pmI don't have much experience in PCB design. I expect to make best use of the wisdom and knowledge shared by forum members.I am going to have a DC-DC switching regulator and MCU on the same board. I will go with 4 layer stack upTop: Signal + Routed PowerInner: GroundInner: GroundBottom: SignalGirish
MAX31865 RTD reference resistance value? - Page 1
Forum section: electronics / projects

author: MotoDan
author_rank: Contributor
timestamp: September 17, 2025, 03:37:36 am
content: So the MAX31865 RTD Temperature Sensor Amplifier datasheet calls for a reference resistance (Rref) of 400 ohm for a PT100 and 4k for a PT1000 sensor, but Adafruit and several other sources have slightly higher values in their designs. Is there a reason not to use the prescribed Rref values?
MAX3221EEUE+ - Noisy charge pump? - Page 1
Forum section: electronics / projects

author: hp23
author_rank: Contributor
timestamp: January 24, 2025, 06:09:45 am
content: Hi, Following a successful EMC test (to meet directive 2014/53/EU), the test house identified a ~30MHz signal. Luckily 7db under class B limit. Following a spot of near field probing, it turns out that the RS232 driver (incorporating a charge pump) was the likely culprit. See enclosed. I've revisited the datasheet & I'm still left a bit stumped. Does anyone have any clues or theories as to why we might be observing this? Nothing else on the board oscillates at this frequency & much of the square wave ringing has been damped elsewhere, so I don't think this is harmonic. TI suggests that the charge pump operates at 100-200KHz.Pete
MAX3232 issue - Page 1
Forum section: electronics / projects

author: JefPatat
author_rank: Newbie
timestamp: January 25, 2017, 08:53:32 pm
content: Hi all,first post here, I have done several projects before but this time I seem to be really stuck, so her I go.I have a small circuit that is supposed to communicate with a heating device using some kind of infrared optolink. I attached the schematic.On my first proto I noticed I forgot to add a capacitor between Vcc and ground, so I soldered one on top of the IC. Because I made a soldering error on the first proto (switched ir led and photo transistor) I made a second one.The issue I am observing is that the circuit is just showing some noise around zero on the TX pin.While making the second proto I only soldered the MAX3232 and its capacitors. I soldered a blob connecting DOUT1 and RIN1 creating a loop back on TTL level. This worked on the PC, I have an USB-RS232 interface and using RealTerm I read back what I was sending. The scope showed levels of +- 7V on TX. I also checked V+ and V- because I saw (in my opinion) strange things on those pins on the first proto. On the second proto I observed the same. V+ a noisy 5V, V- a high frequency signal below zero, somewhere between 0 an -2 if I recall correctly. I was expecting +7 and -7.First question: what should I measure on V+ an V-?Since the loopback test was working I removed the blob and completed the print. To test it I put a spoon underneath so the IR LED reflects back to the phototransistor. This seems to work correctly. Both the green and yellow led blink when I send something from the PC. I also measure a nice 5V with pulses to 0V signal on pin 11 T1IN. I however see only some noise around 0V on the TX pin. Not high, not low, zero?Second question: what am I missing here, this should be a basic circuitIf necessary I can provide scope readings or extra measurements.Thanks in advance,Jef

author: bingo600
author_rank: Super Contributor
timestamp: January 26, 2017, 05:39:42 pm
content: Where did you get the max3232 from ?There are a lot of fakes on *bay , they usually work for a few weeks and then "die"/Bingo

author: tszaboo
author_rank: Super Contributor
timestamp: January 26, 2017, 05:52:05 pm
content: Traditional infrared communication does not use 100% duty cycle, meaning they only transmit for shorter times than the bit length.But a picture is probably better:Also, sometimes it is just modulated with a 38Khz signal.So tell us more.
MAX3421E USB Host IRQ Issue - Page 1
Forum section: electronics / projects

author: jbaum81
author_rank: Newbie
timestamp: July 23, 2023, 07:53:51 am
content: Hi guys,Taking my first adventure down the USB Rabbit hole with the Max3421 setup as host. I'm currently running into an issue where the controller is constantly throwing Peripheral connect/disconnect interrupts while the bus is in the SE0 state. The data sheet says it should only flag the interrupt after going from J or K to SE0 for x ms or vice versa. Going from SE0 to J or K flags an interrupt, I ack and it stays gone. The opposite is not true. I do have the pulldowns enabled for both lines in register 27. Register 18 reports a revision of 0x13. Any help would be appreciated.

author: jbaum81
author_rank: Newbie
timestamp: July 25, 2023, 07:02:07 am
content: Figured it out. I had it set to high speed and SOF frames auto generating which was causing the irq. When I detect a bus event and no J/K state now I'm turning it off until the next bus event and all is well. Well, I'm writing a USB driver in 6502 assembly for USB, as well as can be expected.
MAX4081 - Page 1
Forum section: electronics / projects

author: majdgh
author_rank: Contributor
timestamp: June 11, 2020, 10:04:05 am
content: Hello,I have a question about the Chip MAX4081 gain of 5, I choosed a reference voltage to be 3V for 0.5A full range, so to output will be +-1.5, which in my case at 0A the output will be 1.5V and at 500mA will be 3V and with -0.5A will be 0V BUT:if the load current for some reason is more than 500mA lest say 1A in one direction so will i get a maximum of 3V at the output because the reference is 3V or will i get more?the problem i couldn't find an answer form the datasheet, so i made a simulation in Multisim for the chip and i got more than 3V at 1A! so is it correct that even if the reference voltage is 3V at 500mA so i will get more voltage than 3V or the Multisim module has a problem! Thanks for the answer in advance.

author: exe
author_rank: Unknown
timestamp: June 11, 2020, 11:34:55 am
content: Didn't really dig deep, but looks like it can output more than the reference voltage. Look at Figure 3, the output is an inverting amplifier. So, I guess, maximum output can be close to supply pin.Also, check this in the datasheet:> [...] voltage at the output pin (OUT) that swings above VREF voltage for positive-sense voltages and below VREF for negative-sense voltages. VOUT is equal to VREF when VSENSE is equal to zero.

author: ekiyoha@gmail.com
author_rank: Newbie
timestamp: July 15, 2020, 09:08:18 pm
content: Hello Majdgh,I tried to reply your post about Rigol communication through RS-232 with Ultrascope, but because it is an old post, I was told to write a new topic about. Please check my post "Rigol DS1062C communication through RS-232 with Ultrascope", I just published. regards
MAX4173 Current Sense Amplifier VOUT to VCC Rail Voltage? - Page 1
Forum section: electronics / projects

author: hal9001
author_rank: Regular Contributor
timestamp: October 22, 2021, 06:02:41 am
content: Does the VOUT voltage go up to VCC voltage on current sense amplifiers like MAX4173? What do you find in the data sheet to verify this ?OUT to GND = VCC+0.3V but "Out High Voltage (VCC-VOH)" =1.2V max. Can some one please clarify what this means?Cheers!

author: SiliconWizard
author_rank: Super Contributor
timestamp: October 22, 2021, 07:30:57 pm
content: (VCC-VOH) =1.2V max => means that, as you guessed, the output voltage will saturate at VCC-1.2V (worst case) under normal conditions. So your parameters (Rsense, expected current range) should accomodate that.* For instance, if VCC= 3.3V, Rsense = 20 mOhm and a T version (+20V/V gain), the usable current range will be up to 5.25 A:Vout = Gain * Rsense * IloadVout <= Vcc - 1.2 (worst case)=> Iload <= (Vcc - 1.2) / (Gain * Rsense)Also note that the output will never get down to ground. There's a minimum output voltage (VOL). Consequence is that the minimum measurable current depends on this:Iload(min) = Vout(min) / (Gain * Rsense)If we take VOL = 5 mV (note that it can get better or worse depending on conditions), with the above example, we get:Iload(min) = 12.5 mAThis will be the minimum measurable current. So choose your parameters carefully.

author: hal9001
author_rank: Regular Contributor
timestamp: October 23, 2021, 08:28:59 am
content: Thanks this helps a lot!
MAX485, ok with 2 nodes, when 3rd node powered up voltage drop below 2V (SOLVED) - Page 1
Forum section: electronics / projects

author: stan001
author_rank: Contributor
timestamp: December 29, 2018, 01:46:01 pm
content: Hi,I made a MAX485 module with the schematics below...Everything was working OK when 2 nodes were connected, can Rx or Tx between the master/slave nodes on the Arduino Nano.- I have tried using 20K pull-up/down at A,B or even no pull-up/down on A,B, same results.- I tried with 120R termination or 1K R termination, same results.- Was running at the lowest speed of 9600, same results.I'm using just very short Cat 5E twisted pair cables during the tests..I can visually see it is not working as the Rx,Tx LED becomes very dim or not litted at all..Any idea why does it drop the voltages when 3 or 4th nodes was connected ??Thank you for reading this..MAX485-schWhen running on 2 nodes, everything was ok.MAX485-2nodesWhen connected n power up the 3rd node, voltages dropped below 2VMAX485-3nodesHere is a picture of my setup with the newly made PCB..MAX485-Eduboard

author: capt bullshot
author_rank: Super Contributor
timestamp: December 29, 2018, 02:00:42 pm
content: You have placed a pull-up resistor (R2) on the control input. This puts the output of the MAX485 into active state (transmitting) when nothing is connected. So now you have a transceiver transmitting a static level against your data lines, resulting in the reduced signal level.Change that resistor to a pull-down resistor and it should work.

author: stan001
author_rank: Contributor
timestamp: December 30, 2018, 06:42:05 am
content: Thanks a lot, you are spot on..i removed the 10K pullup and let the Arduino pins control the HIGH/LOW state..
max5035bupa does anyone use this ? - Page 1
Forum section: electronics / projects

author: kripton2035
author_rank: Super Contributor
timestamp: June 13, 2013, 09:25:00 am
content: hi,I'm trying to make a 5v 500mA power supply for my car.I had some max5035 samples lying around so I decided to use them.the ic heats a lot, and cut itself around 200mA, but it is given for 1A !!!I build it following the datasheet schematic.did I something wrong ? I used the dip package, it is given for 1A, and the SO package is for 500mAthanks.
MAX6399 - Undervoltage Lockout Not Working - Page 1
Forum section: electronics / projects

author: waymond91
author_rank: Regular Contributor
timestamp: April 24, 2024, 10:25:19 pm
content: I have a circuit using the MAX6399 acting as an over-voltage and under-voltage lockout.Here is a link to the part:https://www.digikey.com/en/htmldatasheets/production/2916090/0/0/1/max6399I had one small hiccup where I got the gate pin wrong on the pcb, but I have bodged a to-220 onto the pads.I was targetting an overvoltage lockout at 14.4V, and undervoltage at 11.6V. However, the overvoltage kicks in near 13.7V, and the undervoltage never fires.I can measure the "OUT" and "OUT_SET" threshold voltages as I adjust the supply and see they are near their respective thresholds at the appropriate voltage.For example, the undervoltage is near 0.5V at 11.6V, and the overvoltage is near 1.23V at about 14.4VWe had this behaviour after replacing the mosfet but before replacing the MAX6399. I have since replaced the max6399 and get the same behavior.The Schematic3D BoardBoard with bodge mosfet AKA "The Bodgefet"

author: waymond91
author_rank: Regular Contributor
timestamp: April 25, 2024, 03:47:02 am
content: For posterity - the undervoltage cutoff seems to only be hooked up to the ~POK pin and not the GATE pin of the IC
MAX7418EUA+ Newbie question - Page 1
Forum section: electronics / projects

author: Agosto
author_rank: Contributor
timestamp: April 19, 2024, 12:14:56 pm
content: I have the above chip and intend to build a low pass filter. However, the chip housing/package is very small so that I (with my limited skills) can not solder this chip on a board. Can somebody tell me please what options I have? Is there a socket or similar available for such packages?Thanks!

author: Andree Henkel
author_rank: Regular Contributor
timestamp: April 19, 2024, 01:29:05 pm
content: look at the youtube tutorials.this chip is still quite easy to hand solder.fix it diagonally two padssolder all pads with LOT of solder so all pads on side are shortetremove superfluos solder with solder wickin case you want to breadbord buy a adapter pcb to dip and you are reydy to go

author: Agosto
author_rank: Contributor
timestamp: April 19, 2024, 02:20:44 pm
content: Thanks!! Looked at the tutorials. Will give it a try. The adapter to DIP is also a great suggestion. Found them at Digikey. Thanks again!