Identifying a decapped chip marked NE5534 - fake? - Page 1
Forum section: electronics / projects

author: ckocagil
author_rank: Contributor
timestamp: March 01, 2020, 07:48:26 pm
content: Over a year ago I had, in my infinite wisdom, bought 10 pieces of DIP chips from Aliexpress that boldly claim to be TI NE5534 all with the same date/batch code. So I did what any curious and sensible person would do:measured the slew rateboiled it in acid and extracted the die.I took a terrible picture using my phone's camera and a salvaged lens from my parts box. Unfortunately I was unable to find a die image of a real 5534.Zeptobars has an NE5532 image, but that doesn't help me much, does it?So far I have 3 hints that point to this chip being a fake:- Same date/batch code on all chips- The die is absolutely tiny. Longest dimension is at most a milimeter. For comparison, Zeptobars says the TI NE5532 has a die size over 2mm x 2mm.- The silicon is a bit too simplistic..? I would expect a more complicated circuit, but take this with a grain of salt, I have very little clue.Any ideas?

author: Wimberleytech
author_rank: Super Contributor
timestamp: March 01, 2020, 08:47:03 pm
content: Why dont you send one to Noopy and have him do a proper teardown.Looking at the datasheet, I see a 100pf, 12pf, 7pf, and 40pf capacitors. Those will be large and noticeable. I dont see good candidates on your die photo. Moreover, I found this on the interweb. Of course, I cannot vouch for the accuracy.

author: magic
author_rank: Super Contributor
timestamp: March 01, 2020, 08:49:47 pm
content: Quote from: ckocagil on March 01, 2020, 07:48:26 pmThis normally is not a problem, but you are right. When it comes to too-cheap-to-be-true jellybean chips from AliExpress, the only semi-legit ones are batches of mixed-date, mixed-manufacturer recycled ICs.Quote from: ckocagil on March 01, 2020, 07:48:26 pmYep, I have opened some legit 5534s from Philips, TI and JRC and the die size is about 1x2mm in each case. The layout is quite different than half of 5532, by the way, but all the same components are there if you look for them. Minor differences in capacitor area and biasing resistors appear to be responsible for unity gain stability of the 5532.Finally, an immediate giveaway that this is fake is the fact that it's a dual opamp die with only one half connected to the package.editI can confirm that the above picture is a 5534. The four transistors surrounded by capacitors are the 1st and 2nd stage pairs and this block is quite characteristic for 5534/5532. The whole thing looks like 5534.

author: ckocagil
author_rank: Contributor
timestamp: March 01, 2020, 09:14:16 pm
content: Beautiful. With that reference image, the lack of capacitors, and your observation that this is in fact a dual op-amp (I thought it was a bit asymmetric, but that was just bad lighting) we can confirm that this is a fake chip.Thank you folks.

author: magic
author_rank: Super Contributor
timestamp: March 01, 2020, 09:24:35 pm
content: I may add that every legit 5532/5534 has diodes between IN+ and IN- which can be detected with a DMM. This chip probably is a random Chinese LM358 or RC4558 with custom package and a bit of creative wiring to make it work as a single and doesn't have such diodes.Also, those dual-opamp-in-a-single-package fakes have no connection whatsoever to pins 1,5,8. Another easy test with a DMM.

author: Noopy
author_rank: Super Contributor
timestamp: April 20, 2020, 04:17:11 am
content: Coincidentally I have a original NE5534 for you:(credits to floobydust)https://www.richis-lab.de/Opamp01.htmOn the lower left area you can see that diodes magic talked about. On top of that diodes there is the differential stage. And you have the four big capacitors.Did they really modify the mask 2 seven times?Oho...

author: magic
author_rank: Super Contributor
timestamp: April 20, 2020, 05:49:02 am
content: The fourth capacitor isn't big, it's the one above "3B4A41B5A". The metal area in the top left corner doesn't correspond to any capacitor shown on the schematic. It covers collector load resistors of the 1st stage and is connected to VCC, so there is perhaps a few pF of capacitance to those resistors. With kiloohms of resistance, the corner frequency might be multi-MHz . Not sure if it has any effect on normal operation or only blocks RF from getting inside.OP's die is probably identical to 8.JPG herehttps://www.eevblog.com/forum/projects/whats-inside-the-cheapest-and-fakest-jellybean-opamps/That's not even an attempt at cloning the 5534 but some LM358 rubbishAnd finally, contrary to what some people might tell you, it wasn't Signetics who designed this chip (although they may have done the 5532 dual). Look up some Philips TDA1034 datasheet

author: Noopy
author_rank: Super Contributor
timestamp: April 20, 2020, 06:09:50 am
content: Quote from: magic on April 20, 2020, 05:49:02 amOK, big and small are relative statements.The capacitors all in all consume a lot of the die.I would say there are four capacitors and a RC-combination but you are right.Quote from: magic on April 20, 2020, 05:49:02 amQuote from: magic on April 20, 2020, 05:49:02 amInteresting...