Did TI change the TL074C (or did JLC sell me counterfeits?) - Page 1
Forum section: electronics / beginners

author: K3mHtH
author_rank: Regular Contributor
timestamp: July 31, 2025, 03:17:57 am
content: I recently ordered PCBA from JLC and noticed that the power consumption was way different than the previous time I ordered.The only thing i notice so far is that the TI TL074C's look visually different, and since I'm using 18 of them on this project I'm wondering if that is the reason I'm seeing a 20% drop in power consumption.Attached are pictures of the new version followed by the old version.

author: Analog Kid
author_rank: Super Contributor
timestamp: July 31, 2025, 03:21:42 am
content: No TI logo = fake?

author: ataradov
author_rank: Super Contributor
timestamp: July 31, 2025, 04:37:46 am
content: I would ask TI support or sift though their PCNs. Manufacturers do change the markings occasionally. ST recently changed how they mark the parts. I think they also removed the logo. They try to optimize things and make sure the parts can be manufactured on different equipment, some of which may not be able to reproduce the logo at a decent resolution.Even on your reference part it looks like crap. Laser pass takes time, and if the result you get is barely recognizable blob, it is not really worth it.

author: WattsThat
author_rank: Frequent Contributor
timestamp: July 31, 2025, 05:12:36 am
content: 20% change in current with 18 parts or roughly 1% change per device.I wouldn’t call that “way” different.

author: K3mHtH
author_rank: Regular Contributor
timestamp: July 31, 2025, 05:13:49 am
content: Sure, but what explains the drop in power consumption?I'm going to desolder some samples and test them individually to see. Is there another good way to test opamps to see if they're different? check the phase reversal voltage maybe?

author: K3mHtH
author_rank: Regular Contributor
timestamp: July 31, 2025, 05:18:12 am
content: Quote from: WattsThat on July 31, 2025, 05:12:36 amUnfortunately you are mathing wrong. A 20% change in current is a 20% change per device.And actually the individual device current change has to be even higher than 20% because the circuit consists of several other devices that remained unchanged.

author: magic
author_rank: Super Contributor
timestamp: July 31, 2025, 06:22:59 am
content: The logo looks like the middle finger in a circleI think it may be fake, intended to resemble TI without actually using their exact logo. Many such cases.The phase reversal test is a good idea. In my experience with fake Chinese JFET opamps, they are either LM358/LM324 (easy to recognize - high bias current, crossover distortion) or CMOS substitutes. Modern CMOS opamps usually are free of phase reversal, so your test may work.Do you have some means of decapping the Chinese chip?And one more note: TI released "H" versions of TL072 and TL074, which are confusingly marked TL072D or something like that on the package, not TL072C or TL072I as usual. They too are CMOS substitutes, but your chip is marked TL072C so it's something else.

author: gamalot
author_rank: Super Contributor
timestamp: July 31, 2025, 06:47:52 am
content: Quote from: magic on July 31, 2025, 06:22:59 amIt is the "Pin 1 ID"

author: Simmed
author_rank: Frequent Contributor
timestamp: July 31, 2025, 07:26:35 am
content: you have 18 solid parts to show TIbetter ask TI directQuote from: K3mHtH on July 31, 2025, 03:17:57 am

author: Kleinstein
author_rank: Super Contributor
timestamp: July 31, 2025, 07:50:31 am
content: The specs for the current consumption are not tight. There is quite some room from typical to max is large (1.4 mA vs 2.5 mA) and could easy acount for a 20% change. So it could just be a different batch without any internal change. How much is the actual power consumption ?If the did a small change to the die, the tendency would be to make it smaller and get away with less current. I have not checked if there was a PCN (except for the change in the case material - that could also go hand in hand with a change in the labeling).Usually a reduced power consumption is a good thing and no real reason to complain.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 31, 2025, 12:06:10 pm
content: You can test a bunch of other properties of the opamps.With a good film capacitor and the opamp in buffer mode (or positive amplifier) you can check the input impedance by the speed of the drift of the capacitor voltage.with an 100x amplifier you can check both input offset voltage and GBWP. There are quite a lot of simple circuits which can be used to test the non-ideal properties of opamps.You can build a "curve tracer", a.k.a "Signature analyzer" and then compare random pins of the un powered IC with the same pins of a known good IC. These signature analyzers can be as simple as a low voltage mains transformer with a few resistors, to morespecializedexpensive devices such as the Huntron trackers (Gosh, they're still around) and the Electron Plus analyzers.https://huntron.com/products/trackers.htmhttps://electron.plus/collections/analog-signature-analysershttps://duckduckgo.com/?q=IC+signature+analyser&t=h_&ia=web

author: ledtester
author_rank: Super Contributor
timestamp: July 31, 2025, 01:07:04 pm
content: Quote from: K3mHtH on July 31, 2025, 05:13:49 amMaybe look at how clean a square wave it produces, e.g.:https://www.eevblog.com/forum/beginners/op-amp-square-waves/You can tell slew rate and also make a general comparison. In that post the 072 opamps I got from ebay are very suspect.

author: K3mHtH
author_rank: Regular Contributor
timestamp: August 01, 2025, 04:39:37 am
content: So I swapped all 18 of the new TL074C's out with some old TL074C's from a previous JLC order. The power consumption on my project went from 11.8W up to 16W.Between 15.8W and 16.4W is what I have seen on the previous 200 of these PCB's, so swapping to old TL074C's restored this back to the expected power consumption. I also tried some TL074I's I had on-hand from JLC and again the consumption was back in range.So whatever this TI TL074C is from JLC, it is using about 1/4W less energy per package.Some quick math. If each package is using 1/4W less energy, then with my 30V power supply (+15/-15) that is 8mA for the quad package. So 2mA less power consumption in every opamp cell. That seems really suspect to me, like it's actually a TL064 or something entirely different.I also noticed that one part of the circuit was no longer working correctly with the new TL074C. It is doing a phase reversal that's never happened before. Swapping that opamp out for one of the old ones corrected the behavior immediately.So: 2mA less quiescent current per cell and lower threshold before phase reversal.If anyone wants to decap and inspect this thing, I have plenty (along with the old versions) and can mail them out

author: ataradov
author_rank: Super Contributor
timestamp: August 01, 2025, 04:49:42 am
content: There is TI PCN # 20221219006.1 that affects this device. They moved it to a new process node and qualified new assembly site. This can lead to changes in both electrical characteristics and visual appearance of the device.I would contact TI and ask them if this is expected of the new devices.They don't call it out specifically, but they don't have to as long as min/max values are still the same.

author: Simmed
author_rank: Frequent Contributor
timestamp: August 01, 2025, 06:42:02 am
content: Quote from: K3mHtH on August 01, 2025, 04:39:37 amask noopyhttps://www.eevblog.com/forum/projects/opamps-die-pictures/725/

author: Kleinstein
author_rank: Super Contributor
timestamp: August 01, 2025, 08:42:31 am
content: Quote from: ataradov on August 01, 2025, 04:49:42 amThe PCN looks like they changed from the original TL07x to the CMOS TL07xH. This is very confusing as for quite some time they had both parts in parallel. The situation with the H vesion was confusing enough, but a simple PCN and changing old numbers to the CMOS version is really bad practice.The versions are somewhat similar, but still different in relevant parameters: lower power, lower distortion, but also higher noise, especially 1/f noise.So the TL07xH can not fully replace the old version. The lower power consumption would be acceptable, but more than 2 x the noise at 1 kHz (and even worse at 10 Hz) is too much.To get to old JFET parts one may have to be careful with the part number and maybe call for parts from ST or ON instead.I otherwise like Ti parts, but I would avoid TL07x from Ti unless one specificly wants the new CMOS version.

author: magic
author_rank: Super Contributor
timestamp: August 01, 2025, 09:20:20 am
content: If you have the chips desoldered, check them for internal diodes with a DMM.TL072 should have:VCC- ---|>|--- IN+VCC- ---|>|--- IN-VCC- ---|>|---|>|--- OUT (that's TI, but my Motorola TL071 seems to have VCC- ---|>|--- OUT)OUT ---|>|--- VCC+TL072 should never have:IN+ ---|>|--- VCC+IN- ---|>|--- VCC+IN+ ---|>|--- IN-IN- ---|>|--- IN+Quote from: Kleinstein on August 01, 2025, 08:42:31 amAre you sure? That was a few years ago, but TI's latest datasheet still lists H version and the others separately, with different specs and plots. I think they just moved their BiFET process to another fab.

author: tooki
author_rank: Super Contributor
timestamp: August 01, 2025, 11:41:40 am
content: Quote from: Kleinstein on August 01, 2025, 08:42:31 amThe TL07x datasheet has guidance on this. (See screenshots, attached.)It contains separate specs for the H and non-H versions. The non-H versions (in most package types) seem to retain the old specs.

author: mawyatt
author_rank: Super Contributor
timestamp: August 01, 2025, 12:37:36 pm
content: Quote from: K3mHtH on August 01, 2025, 04:39:37 amThe Phase Reversal is a good indication of a different type/process/OEM device. Does the circuit that has the Phase Reversal have the inputs outside the CM range? Recall way back when certain National Bi-FET op-amps exhibited this behavior when the inputs were overdriven, but thought this was corrected in later versions.Best

author: wraper
author_rank: Unknown
timestamp: August 01, 2025, 01:06:01 pm
content: Quote from: tooki on August 01, 2025, 11:41:40 amIt says that buying anything except H (guaranteed new process) and M (guaranteed old process) is a crapshoot of what you'll actually get.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 01, 2025, 01:06:30 pm
content: Quote from: tooki on August 01, 2025, 11:41:40 amAccording to the new datasheet and PCN the new die (CMOS version) is no longer found only in the H version. It is only the M version (extended temperature) and PS / NS case (wide SO8/14 and thus a more rare case variant) that are definitely the old JFET version. The more common narrow SO case may be the old version, but could also be the new CMOS version. So they can not retain the old specs as the CMOS version has roughly 2 x the noise. So really a point to watch - maybe avoid the poorly defined Ti parts if you care about noise.From the common mode range and chance for phase inversion the CMOS version has slightly better specs. There is still quite some scattering in the old version. One might still get latch up in cases where the JFET version, was saved by a more limited output drive.

author: SCSKITS
author_rank: Regular Contributor
timestamp: August 17, 2025, 07:51:42 pm
content: So the current went down. Lots of comments about the current, did not get to all of them. Real question is "does the board still function properly to specifications?). If it does, you are good to go. If not, there is a problem with either the parts or the design. One more thing, parts (from the same manufacturer) made in different facilities or countries can have different characteristics. Sometimes one will work and the other may or may not, depending on the circuit.

author: gerber
author_rank: Newbie
timestamp: August 19, 2025, 01:23:47 pm
content: TI will only give support for components procured through their authorized distributors.Quotesource:https://www.ti.com/ordering-resources/faqs/purchasing-online/authorized-distributors.html