LTZ1000ACH fake? - Page 1
Forum section: electronics / general

author: faraday
author_rank: Regular Contributor
timestamp: March 27, 2025, 02:58:30 pm
content: Is it real or fake? I got it form ebay and drift like hell.

author: Overspeed
author_rank: Frequent Contributor
timestamp: March 27, 2025, 03:59:59 pm
content: HelloYour engraving looks coarse and on samples I have in pictures that not engravingcan you make a picture of the pins side ?RegardsOS

author: dietert1
author_rank: Super Contributor
timestamp: March 27, 2025, 04:03:32 pm
content: What means "like hell"? Would you show a log?

author: Kleinstein
author_rank: Super Contributor
timestamp: March 27, 2025, 04:54:37 pm
content: The LTZ1000 needs extra external circuit for low drift operation. Drift an also be from this part of the circuit.If it works at all, chances are it would be a real chip. AFAIk there is no direct pin compatible chip - closed would be ADR1000 and thus would be too new and lower voltage.There is a chance to get reclaimed chips and these can also be damaged (like broken heater). There is also a chance to have a non working circuit around the ref, like oscillating temperaure regulator or no regulation (e.g. to low a set temperature).

author: aronake
author_rank: Frequent Contributor
timestamp: March 27, 2025, 06:00:20 pm
content: it looks suspicious....what heater resistance? i.e. between pin 1 and pin 2? It should be between 200 and 420 ohm. If not that may indicate fake or a broken heater.

author: Andreas
author_rank: Super Contributor
timestamp: March 27, 2025, 06:52:23 pm
content: Hello,be shure that pin 1 is the more positive during measurement of heater resistance.(Reverse biasing might damage the device)Did you use the datasheet cirquit for drift measurement?How much was the Temperature signal and the heater current?on the other side. The package looks also suspicious to me.The "rounded hat" and obviously engravement.(does not look like laser marking introduced since 2019/2022 on one fab).with best regardsAndreasEdit: on the other side it looks very much like here in Richis Lab:https://www.richis-lab.de/REF44.htm

author: Overspeed
author_rank: Frequent Contributor
timestamp: March 28, 2025, 09:26:09 am
content: HelloEngraving looks suspicious as the number 4 have a scratch cut by the engraving so the scratch was before the engraving , this kind of $$ components are carefully handled and quality inspected I doubt surface damaged components have been accepted by QCRegardsOS

author: AnalogTodd
author_rank: Regular Contributor
timestamp: March 28, 2025, 12:25:36 pm
content: I worked at LT for many years and never knew us to engrave metal cans like this. Granted, I left in August of 2020 and the date codes on these are 2022, so I can't speak for what may have been changed in the last few years after the acquisition by ADI.While it may be a real LT die inside, there have been times where packaged devices that failed testing were unscrupulously removed from the test floor and made their way through 'secondary' markets into customer hands.

author: faraday
author_rank: Regular Contributor
timestamp: March 28, 2025, 04:41:20 pm
content: THX for all answers after 2 days it stabilized and it starts looking good . It seems to be genuine.

author: Overspeed
author_rank: Frequent Contributor
timestamp: March 28, 2025, 07:58:40 pm
content: Quote from: faraday on March 28, 2025, 04:41:20 pmHelloI share the point of Analogtodd , inside perhaps , outside surely not , a lot of component on the grey market are factory second rejected , sometime components are rejected for minor defects or a tiny tolerance out of specs .If that work that a good thing for youRegardsOS

author: floobydust
author_rank: Super Contributor
timestamp: March 28, 2025, 08:34:51 pm
content: PCN 22_0025 June 2022 converting from ink top mark to laser mark. Many parts like LM399, ADR1399, LTZ1000 etc. COO is supposed to be on the side of the can?PCN 22_0014 March 2022 Final packaging changed from ADI Singapore to ADI Phillipines (TO-46, TO-5, TO-92)There's other changes.OP's part with scratches and scuff marks, looks like typical china fair? Unless these IC's get handled rough, many steps.

author: aronake
author_rank: Frequent Contributor
timestamp: March 28, 2025, 11:25:07 pm
content: Quote from: faraday on March 28, 2025, 04:41:20 pmHow do you test it? what design of board do you use, and what resistors? How do you measure if it has stabilized?

author: faraday
author_rank: Regular Contributor
timestamp: March 29, 2025, 07:38:55 am
content: I got this board from 2nd hand when I powered for the first time it had some wierd spikes ( see attached picture) I left it over night and it did second log.

author: dietert1
author_rank: Super Contributor
timestamp: March 29, 2025, 08:08:37 am
content: That kind of asymmetric noise with negative spikes indicates a supply problem.The board may work better if you feed the reference using the on-board buffer cap C5 and the on-board 7812 regulator. You can use the AC input terminal (green screw terminal) with 17 V DC or more. It may be better to bridge D7 if that diode reduces 12 V of the regulator to 11.3 V.

author: faraday
author_rank: Regular Contributor
timestamp: March 29, 2025, 09:52:29 am
content: Quote from: aronake on March 28, 2025, 11:25:07 pmBoard use Vishay0,01% resistors