TLE2144: output signal distortion;

Depeng Man

Intellectual 2030 points

Part Number: TLE2144

Hello Team,

I am currently using a TLE2144IDW, and the input signal of 600 kHz, 4.2Vpp is generated from a function generator.

Using a voltage follower with TLE2144, I was able to get an output of 4.2Vpp with an input from the function generator, but after it reaches above 510 kHz, the signal starts to distort on the negative cycle.

The gain bandwidth of TLE2144 is around 5 MHz, and the slew rate is 27 V/μs. Therefore, I should be getting a good signal on the output, yet the negative cycle of the signal looks slightly distorted. Not sure what the issue is. I do not know what I need to look for.

Schematic:

Dual Supply of +/-12 V

Image shown below (input: cyan signal, output: yellow signal):

I hope to hear from you on this.

Best Regards

James Man

over 3 years ago

0 Raymond Zhang1 over 3 years ago

TI__Guru* 77501 points

Hi James,

We are a bit short-handed today. The reason that you see distortion is that there is a Q or gain peaking near the BW of the op amp.

Please try the following compensation, and see you are able to get around the issue.

TLV2144 330uH 55Ohm Load 10312022.TSC

Best,

Raymond

0 kai klaas69 over 3 years ago

Guru 140200 points

Hi James,

Depeng Man said:
The gain bandwidth of TLE2144 is around 5 MHz, and the slew rate is 27 V/μs. Therefore, I should be getting a good signal on the output,

Sorry that I disagree with you, but the TLE2144 is not fast enough to give a pure and clean 600kHz sine wave at the output. Because the gain bandwidth of TLE2144 is 5.9MHz, you have a linearizing gain reserve of only about 5.9MHz / 600kHz = 10V/V or 20dB. This is way too little to reproduce a clean sine wave of 600kHz. I would choose an OPAmp with a gain bandwidth of >60MHz.

Kai

0 Depeng Man over 3 years ago in reply to Raymond Zhang1

TI__Intellectual 2030 points

Hello Raymond,

Thank you for your quick reply.

I've conveyed it to my customer.

Have a good day .

James

0 Raymond Zhang1 over 3 years ago in reply to Depeng Man

TI__Guru* 77501 points

Hi James,

Please let us know if the issue is resolved.

Kai is correct, if the customer requires a low distortion sine wave application, where the BW of the op amp needs to be higher for 600kHz signal.

Best,

Raymond

0 Raymond Zhang1 over 3 years ago in reply to Raymond Zhang1

TI__Guru* 77501 points

Hi James,

I am going to close this inquiry. If you have additional questions, please let us know.

Best,

Raymond

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TLE2144: output signal distortion;