INA128: Is it a fake?

What error? Please explain in detail.

Kai

Normally, the output voltage changes about twice the gain setting with respect to the input voltage.

As for the defective product, -1.57V, -13.78V and 14.12V are always output, and the output voltage does not change with respect to the input voltage.

Hi,

Can you please share a picture of your schematic including:

• voltage supplies
• reference voltage
• common mode voltage
• input signal
• expected output signal

I will help you review this.

Also, you may consider taking a look at our INA828. It is the new version of INA128.

Another question: where did you purchase the parts from? 51AL0S isn’t the full marking, so I would need more details.

Hi user6422847,

Let's answer your question first. 

Do the following ICs actually exist? (Is it genuine?)

Device name: INA128UAE4

Lot number: 51AL0S

The device name is correct,  however, I would need more details. 51AL0S is not the full marking. Can you tell us where are you purchase the IC from? Who is your part distributor?

Best,

Raymond

0181.INA128調査条件.pdf

【NG LOT】

【OK LOT】

[Purchase route]

Our company

　　↓

(Japan) Distributor A

　　↓

(Japan) Distributor B (Import)

　　↓

(China) Distributor

LABO Electronics CO., LTD

Rm.402 4 /F, Gongyi Building   Zhenhua Road, Futian District, Shenzhen, China

6087.INA128調査条件.pdf

【NG LOT】

【OK LOT】

[Purchase route]

Our company

　　↓

(Japan) Distributor A

　　↓

(Japan) Distributor B (Import)

　　↓

(China) Distributor

LABO Electronics CO., LTD

Rm.402 4 /F, Gongyi Building   Zhenhua Road, Futian District, Shenzhen, China

Hi user6422847,

We will get back to you tomorrow. 

When I saw the green framed box, I thought that the issue may be resolved. Perhaps it was a mistake. 

From the images you provided, I do see that "NG LOT" does use different marking process (at least they are originated from to different fab houses). We will let you know tomorrow. 

Best,

Raymond

Hi user6422847,

Here is what we found:

Both parts (shown in image( are located within the TI system, so the parts are good. 

The device label 51AL0SK is dated from 2015, which is out of manufacture warranty at this point. 

Did you check for cold soldering issues, shorts or poor conductivity issues? Regarding the part's functionality, can you retouch each pin with solder iron in the questionable part? I was wondering if the part has surface oxidation issues that prevent the part to make good electrical contact. 

I do not see issue with your schematic. If you have other questions, please let us know. 

Best,

Raymond

Thank you for your reply.  There were no abnormalities such as solder mounting conditions or shorts.  When I replaced the NG LOT product with another IC, all became OK.  If the surface is oxidised and the power is turned on, is it possible that the phenomenon will look like it was sent?  Also, under what conditions will the phenomenon such as output abnormality occur?

Hi user6422847,

How many 2015 INA128 parts do you have? Can you solder one by hand on a PCB and see if it will work? Our current theory is that the moisture issue absorbed inside of INA128s. 

Here is the possible explanation about why the part may go "bad". 

When the parts are left on a shelf for a long time, significant amount of moisture can be absorbed in the encapsulation material and/or within the package. If this is case, it is recommended to bake these parts in an oven before use, see the attached application note. 

With the absorbed moisture inside of IC package, the internal IC part may get damaged during wave or reflow soldering process due to excessive heated moisture pressure inside of the IC, which it may "explode" inside of IC and cause internal IC damages. The heated moisture inside of IC cavity is pressurized and has nowhere to go and "explode" inside of IC package, which it causes damages (some surface moisture is released into the soldering chamber, but not the moisture absorbed inside of encapsulated IC). 

Enclosed is the application report AN-2029, which is TI's recommendation in handling and process surface mount IC packages (per IPC/JEDEC J-STD-033 recommendation).  

https://www.ti.com/lit/an/snoa550h/snoa550h.pdf?ts=1598118338065&ref_url=https%253A%252F%252Fwww.google.com%252F

If you have additional questions, please let us know. 

Best,

Raymond

Thank you for your reply.
When 18 of the mounted products were inspected, 15 were defective.(IC: 3 pcs / 1 unit)
Breakdown of inspection OK products (3 units)
2 units: Lot / 99C8L9 IC was mounted.
1 unit: Mixed (1 pcs 51AL0S, 2 pcs 99C8L9).
ALL NG products were equipped with 51AL0S.
Fifteen units operated normally after replacing the lot/99C8L9 ICs.
One confirmation, even if one of the three has 51AL0S mount
If it is operating normally, will it not become defective over time?
(Isn't there a defect due to the change with time after that if the IC that absorbs moisture is used and it operates normally during inspection?)

Hi user6422847,

There are 8 pins in INA128 instrumentation op amp. Without knowing the specific non-functional part of blocks, I would recommend checking the IC by functional blocks and narrow down the possible damages. You may have to compare the "damaged" units with reference or good units. Prior starting with following tests, please visually inspect the part under microscope (100-200X or so) and record any physical damages in these parts. 

1. with a high impedance ohmic meter, check the DC resistances of pins vs. ground or between each functional blocks. For instance. Pin2 and Pin3 should be high impedance. Although this test may not conclusive, but it will give you ideas if pins' DC resistances are different. Pay specific attention why these pins are different. The issues are that the damages can be different from parts to parts, and it may not have a specific pattern. 

2. Check the power input rails voltage vs. input current, and check for difference. 

3. Pin6 and pin1 should have a resistance path, so is pin5 and pin 8 --> see if they are ok. 

4. Check the Vout in pin6 vs. inputs (pin2 and pin3), see it the output follows the transfer functions. 

5. If you really want to see what was going on, you can decap the IC, and inspect the inside of  a part  --> but this is a lot of work. 

Again, the damages in each part will likely be different, if there were mini popcorn explosion inside of ICs due to high heating rate and built-up steam pressure inside of IC. Package may be cracked, internal bonding wires may be missing, film delamination or etching due to mini explosion etc..  

If you need further assistant, please let us know. 

Best,

Raymond 

Hi user6422847,

I recalled that your non-functional parts are dated back in 2015, and these parts are out of warranty period currently. 

Generally, our defective parts can be returned and analyzed via the following methods and requirements. 

 https://www.ti.com/support-quality/additional-information/customer-returns.html?keyMatch=CUSTOMER%20RETURNS&tisearch=Search-EN-everything

https://www.ti.com/lit/ml/sprac01a/sprac01a.pdf?ts=1600790679132&ref_url=https%253A%252F%252Fwww.ti.com%252Fsitesearch%252Fdocs%252Funiversalsearch.tsp%253FsearchTerm%253DGuidelines%2Bfor%2Breturns

https://www.ti.com/support-quality/additional-information/failure-analysis.html?keyMatch=FAILURE%20ANALYSIS&tisearch=Search-EN-everything

The application supporting team does not involve with the returning process. I would recommend that you may communicate with your distributor and see what they will propose. 

Since the damaged part is likely due to the humidity issues within the IC package, you may work with your supplier to resolve these process issues. Your supplier should have these test equipment to troubleshoot the lists that I suggested. Alternatively, you may send the sample out to 3rd party vendor who is specialized to perform the failure analysis. 

If you need further assistant, please let us know.

Best,

Raymond