TL082: Failure problem

Zoey Wu

Part Number: TL082

Tool/software:

hi team,

my customer found that the resistance of one chip TL082 is abnormal when system runs normally. The problem occurs once in every 1000pcs. The resistance is as shown in below excel. Customer wants to know which could result to this kind of failure. thanks!

7 months ago

0 Raymond Zhang1 7 months ago

TI__Guru* 77541 points

Hi Zoey,

Zoey Wu said:
my customer found that the resistance of one chip TL082 is abnormal when system runs normally. The problem occurs once in every 1000pcs.

The input DC resistance in op amp's pins are not the standard screening process to determine GOOD or BAD amplifiers. It is ok to say that two batches of op amps are different. The PASS/FAIL criteria is arbitrarily defined by customer based on the history of the received op amps.

The issues are TL082's FAB has changed recently, and that is why the customer is seen differences. Here are related PCN in this part.

https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/5488/PCN20230627002.1.pdf

https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/4884/PCN20211123004.0.pdf

https://www.mouser.com/PCN/Texas_Instruments_PDN20240404000.3_Addendum.pdf

The new TL082 is manufactured from the upgraded FAB. Both old and new TL082 op amps are equivalent in performance, but certain performance may be slightly different. It is suggested to check the new FAB out, and it may require slight circuit modification for the existing design, which I can help (you need to send me the schematic and I will be happy to check it out).

In general, the new FAB op amp has better performance and better consistency than the old Si design.

If you have other questions, please let me know.

Best,

Raymond

0 Zoey Wu 7 months ago in reply to Raymond Zhang1

TI__Expert 5925 points

hi Raymond,

thanks for your reply!

Here is the schematic of customer. Could u kindly help to look into this? Especially whether the resistor of R509&R510 are suitable or not? thanks!

0 Clemens Ladisch 7 months ago in reply to Zoey Wu

Guru 318300 points

The schematic does not show the TL082 but the TL082H. There was no PCN for the TL082H.

What is the possible range of output voltages for U500A? What is the desired range of input voltages at U501?

With the full ±15 V at U500A's output, the output current could be 35 mA, which would be too much. By increasing R514, you would be able to use a smaller current.

0 Zoey Wu 7 months ago in reply to Clemens Ladisch

TI__Expert 5925 points

hi Raymond, the output range of TL082 is ±5 V , the input range of U501 is ±250mV. Are there any problems? thanks!

0 Raymond Zhang1 7 months ago in reply to Zoey Wu

TI__Guru* 77541 points

Hi Zoey,

Clemens Ladisch said:
There was no PCN for the TL082H.

The record is shown the TL082H is in RFAB, and PCN is related to 20230627002 series. The reason the part does not have PCN is that TL082H is designed in RFAB first; then use it as the baseline to convert the existing TL082C and TL082I to RFAB. TL082H is manufactured in RFAB process.

Clemens Ladisch said:
What is the possible range of output voltages for U500A? What is the desired range of input voltages at U501?

The input common mode range in this part is shown in the label below. The output can swing close to Vcc, depending on the load and current level. The nominal output current may be able to source/sink up to +/-17mA range depending on the Tamb, see the plots below. Isc is rated at approx. +/-26mA at room temperature.