TL082-Q1: TL082QDRQ1

user4958508

Part Number: TL082-Q1
Other Parts Discussed in Thread: TL084, TL082

We purchased the device through mouser on September 2, 2019. Brand: Ti model: tl082qdrq1 quantity: 250pcs Batch: 1804.

The output waveform of the chip is as follows: the peak duration of the output pin of the normal module power on chip is relatively short, and the peak duration of the abnormal module power on chip is about three times of the normal.
Defect rate: 17 / 80 = 21%. The picture on the left is normal device, and the picture on the right is bad device

over 4 years ago

0 kai klaas69 over 4 years ago

Guru 140200 points

Hi,

we need a schematic and scope plots.

Use the "Insert File" button (paper clip) in the header of text box.

Kai

0 user4958508 over 4 years ago in reply to kai klaas69

Prodigy 50 points

Hi The picture on the left is the normal output waveform of the chip, and the picture on the right is the abnormal output waveform of the chip.

0 kai klaas69 over 4 years ago in reply to user4958508

Guru 140200 points

Hi,

looks like an oscillation due to a too high capacitive load. What is connected to the output of TL084? Is a phase lead capacitance mounted in the feedback loop? Can you show a schematic?

Can you show a scope plot with another time scale (horizontal axis) showing the higher frequency components of bad signal?

Kai

0 user4958508 over 4 years ago in reply to kai klaas69

Prodigy 50 points

HI，

We provide tl082 for discussion, and your reply is tl084. Please help to confirm whether the reply is wrong. Thank you

0 kai klaas69 over 4 years ago in reply to user4958508

Guru 140200 points

Hi,

this was just a typo. But it won't make any difference here, because the TL084 and TL082 behave identically.

Kai

0 Ron Michallick over 4 years ago in reply to kai klaas69

TI__Guru*** 140146 points

User 4958508,

As Kai mentioned, oscillation can occur if the stability of the amplifier loop is poor. Zoom into the output difference on the oscilloscope and look for possible oscillation. Also verify the the input common mode voltage is between [VCC-] +4V and [VCC+] - 4V

0 user4958508 over 4 years ago in reply to Ron Michallick

Prodigy 50 points

Hi；

We are now tested for device replacement. For the same circuit board, replace the defective tl082 with a new tl082, and the problem will disappear. The circuit board functions normally. All of us doubt that tl082 device itself is not bad. Thank you

Alex.wan

0 kai klaas69 over 4 years ago in reply to user4958508

Guru 140200 points

Hi Alex,

because of the high defect rate of 21% mentioned in your first post I think that you still have a stability issue in your circuit.

Kai

0 user4958508 over 4 years ago in reply to kai klaas69

Prodigy 50 points

Hi. Kai:

Our company fully complies with your requirements in the use of this device.

Under the same production conditions, tl082qdq1 chips of other batches did not show any defects in the production line and the end of use. In addition,

our company has replaced tl082qdq1 with a new one in the invalid products, and the products can also operate normally.

Therefore, your company will take back the invalid parts for test! Thank you

Alex.Wan

18621595172

0 kai klaas69 over 4 years ago in reply to user4958508

Guru 140200 points

Good luck!

Kai

0 Ron Michallick over 4 years ago in reply to kai klaas69

TI__Guru*** 140146 points

Alex,

I understand your viewpoint. If you decide you need troubleshooting help later, just post a new reply or chose ask a related question option.

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TL082-Q1: TL082QDRQ1