OPA171: Vo variation data

Koji Ikeda

Expert 6705 points

Part Number: OPA171

Hello support team,

Customer inquires if you have any data of OPA171AIDRLR Vo variation with their usage setup. Do you have any data?

*Ta: 0 degC to 85degC

*V-:0V, V+: 5V

Thanks,

Koji Ikeda

over 4 years ago

0 Robert Clifton56 over 4 years ago

TI__Mastermind 29250 points

Hello Ikeda-san,

We don't measure the variation across temperature range. We only look to see if it meets our min/max spec requirements.

Let me know if there's anything else you need!

Best Regards,

Robert Clifton

0 Koji Ikeda over 4 years ago in reply to Robert Clifton56

TI__Expert 6705 points

Robert-san,

Thank you for your support. But, did you measure any data for Vo during development? Or your assumption ( no guarantee) is very helpful for them.

Thanks,

Koji Ikeda

0 Robert Clifton56 over 4 years ago in reply to Koji Ikeda

TI__Mastermind 29250 points

Hello Ikeda-san,

During development we did capture data for the datasheet like the no phase reversal (shown below).

The test conditions aren't the same as what your customer is asking for hopefully this helps. Other than this, we don't have any other measurements besides the absolute min/max.

Best Regards,

Robert Clifton

0 Koji Ikeda over 4 years ago in reply to Robert Clifton56

TI__Expert 6705 points

Robert-san,

I assume that you measured high volume sample data to define the spec, could you assume the variation min/max of their usage condition?

Thanks,

Koji Ikeda

0 Clemens Ladisch over 4 years ago in reply to Koji Ikeda

Guru 321020 points

Figure 9 shows typical temperature variations (those at 5 V will be similar), but there is no guarantee.

The guaranteed limits are tested, and failing devices are not sold. So it is possible to for the actual variation to change without affecting the datasheet limits.

0 Robert Clifton56 over 4 years ago in reply to Clemens Ladisch

TI__Mastermind 29250 points

Hi Ikeda-san,

Clemens is right. Any device that doesn't meet the min/max in the test conditions described in the datasheet, aren't sent to customers.

Is there a reason for the customer's concern for variations in the min/max?

Best Regards,

Robert Clifton

0 Koji Ikeda over 4 years ago in reply to Robert Clifton56

TI__Expert 6705 points

Clemens-san, Robert-san,

Thank you very much for your support. In their mass production product, their output design can't meet the spec, they really need our feedback. If you don't have data with their setup, can you show the following information?

*How does the Vo performance or variation changes by Vs max 36V and 5V? Assume same?

*Do you have variation data or histogram of the min/max 0.36V on Vo spec?

Thanks,

Koji Ikeda

+1 Robert Clifton56 over 4 years ago in reply to Koji Ikeda

TI__Mastermind 29250 points

Hello Ikeda-san,

I apologize for misunderstanding. I didn't realize this was already in mass production! Can you provide us the customers schematic? If it's private information we can move to an internal thread. I will check to see if there's any resources we might have taken on a bench in the meantime.

Best Regards,

Robert Clifton

0 Koji Ikeda over 4 years ago

TI__Expert 6705 points

Part Number: OPA171

Hello Support team,

I closed post on public and create new post in internal one.

https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/1062841/opa171-vo-variation-data/3936263#3936263

Could you support the following item?

*How does the Vo performance or variation changes by Vs max 36V and 5V? Assume same?

*Do you have variation data or histogram of the min/max 0.36V on Vo spec?

If you need, I will request them to share their schematic, but, they might expect full support which can be satisfied with their full expectation... Probably, Vo variation spec would not be changed by external schematic, so your setup might be OK.

Thanks,

Koji Ikeda

0 Ron Michallick over 4 years ago in reply to Koji Ikeda

TI__Guru**** 170196 points

Ikeda-san,

Any reply that comes after accepting answer will reopen thread. Robert will reply shortly.

0 Robert Clifton56 over 4 years ago in reply to Ron Michallick

TI__Mastermind 29250 points

Hello Ikeda-san,

We are still on the external forum.

There is very little change 5V to 36V supplies because the gate drive is fully present at 5V. Below 5V the output drive does get notably weaker.

One condition I didn't mention before was if the customer is causing the op-amp to output a high amount of current. With higher current draw, the output voltage won't be able to hit the output voltage swing specs.

Is the customer driving a low impedance load?

Best Regards,

Robert Clifton

0 Koji Ikeda over 4 years ago in reply to Robert Clifton56

TI__Expert 6705 points

Robert-san,

Thank you for your support.

Please let me confirm, what is output load condition for Vo spec +/-0.35V? 18V / 10kohm = 1.8mA?

Fig.9 is TYP information, while they need variation.

Thanks,

Koji Ikeda

0 Koji Ikeda over 4 years ago in reply to Koji Ikeda

TI__Expert 6705 points

Robert-san,

OPA171A output is connected to MCU port directly, without any load resister. And their concern is bottom side near V-:0V only. How the TYP value changes with Vs:5V, no load and 85degC? And again, they need the variation information, too.

Thanks,

Koji Ikeda

0 Robert Clifton56 over 4 years ago in reply to Koji Ikeda

TI__Mastermind 29250 points

Ikeda-san,

The Vo max/min specs from the electrical characteristics table were tested with a 10kohm load. So the current draw was likely around 1.8mA in this test application.

Is the MCU port that they are connecting to an internal ADC? If not, what is it? There's likely some input resistance.

If there's truly no load then Vol and Voh will be within 2mV of the supply rails.

Best Regards,

Robert Clifton

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OPA171: Vo variation data