TINA --ths3091

zhang ping

Other Parts Discussed in Thread: THS3091

We have finished assemblied and tested the simple non-invert input amplifier using ths3901.

The schematics is as follows:

In real circuit, we replace the AM1 and AM2 current meter with 100mR current shunt resistors and measures the crossed voltages by a Keysight 6 1/2 DMM.

The measurement results show both AM1 and AM2 are about 9mA (actual voltage cross the 100mR resistor is 0.9mV).

However, the simulated results in TINA are different, which are as follows:

You can see the simulated current is almost double than real circuit values. So can you help us to identify the reasons?

over 6 years ago

0 Karan Kotadia over 6 years ago

TI__Genius 16735 points

Hi,

Can you upload this TINA file you have created?

Thanks!
-Karan

0 zhang ping over 6 years ago in reply to Karan Kotadia

Genius 3835 points

TH3091_NonInvert.TSC

0 Michael Steffes over 6 years ago in reply to zhang ping

Guru 48395 points

Hello Zhang, aside from the supply current mismatch you realize you have massively bandlimited this CFA using too high an Rf value.

Stability and BW optimization if you need more BW is discussed here -

www.planetanalog.com/author.asp

0 Michael Steffes over 6 years ago in reply to Michael Steffes

Guru 48395 points

I would say the model is just in error on the supply current - what you measure is about right.

0 Karan Kotadia over 6 years ago in reply to Michael Steffes

TI__Genius 16735 points

Hi Zhang,

As michael mentioned, the current should be about 9.5mA which is close to what you measured. I am not sure what is wrong with the TINA model. I will have someone take a look at the model and get this corrected. Is there any particular issues that you are facing with this device?

Thanks!
-Karan

0 zhang ping over 6 years ago in reply to Karan Kotadia

Genius 3835 points

THS3091 heated up to 70 degrees Celsius in my circuit. I checked the power consumption of operational amplifier by simulation, and found that the actual and simulation did not match.

Actual measurement THS3091 Iout = 16mA, IVs + = 32mA, IVs - = 50mA. The input signal is about 3V square wave, with a rise/fall time of about 2us and a period of more than ten us.

0 Karan Kotadia over 6 years ago in reply to zhang ping

TI__Genius 16735 points

Hi Zhang,

It seems that the power consumption values provided on the TINA model are incorrect.

What package are you using? Is it the D package? The datasheet contains a Junction to ambient thermal as 113.5 C/W for the D package. Using the 9.5mA IQ and the 24V input voltage. We get a power consumption of .228W. So we get a temperature of 113.5*.228 = 25C. Assuming an ambient temp of 25C we get a total temp of 50C. This is close to the 70C that you are getting. A quick solution if you are using the D package is to switch to a DDA package. Based on the currents you are drawing, it is very likely that the 70 degrees C is expected behavior.

Thanks!
-Karan

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TINA --ths3091