LMH6554: Request for Guidance on LMH6554LEE/NOPB Differential Amplifier Configuration

Samudra Jampani

Part Number: LMH6554
Other Parts Discussed in Thread: INA333

Tool/software:

Dear Sir,

We are using the LMH6554LEE/NOPB differential amplifier in our custom project.
In our design, we feed a 3.8 GHz RF signal into an RF power detector (LT5538).
The power detector provides an output voltage corresponding to the input RF power level.
This output is then passed through a differential amplifier and a filter, and finally fed into the ADC inside the STM32 microcontroller.

Could you please suggest whether we should use AC coupling or DC coupling between the LT5538 and the LMH6554LEE/NOPB?
Also, could you recommend a suitable reference circuit for configuring the LMH6554LEE/NOPB?
The amplifier should only amplify the output signal of the power detector and should not amplify or shift the ADC reference voltage (offset).

Thank you for your support.

Best regards,

Samudralankaiah.

6 months ago

0 Samudra Jampani 6 months ago

Prodigy 55 points

And we are using single-supply operation, so AC coupling is used at the input side.
Please find the attached schematic snippet for your reference.

0 Alec Saebeler 6 months ago in reply to Samudra Jampani

TI__Mastermind 23269 points

Hello Samudra,

I need to take time to review the circuit and also understand the front-end RF power detector.

I will add an update once I have information to share.

Thank you for the schematic and information.

Best,

Alec

0 Samudra Jampani 6 months ago in reply to Alec Saebeler

Prodigy 55 points

Dear Sir,

Sure, Sir. I am also attaching the single-ended configuration using a different amplifier.

Both configurations are part of the project. We are using them with both single-ended and differential channel ADCs.

Thank you so much sir

Best regards,

Samudralankaiah.

0 Alec Saebeler 6 months ago in reply to Samudra Jampani

TI__Mastermind 23269 points

Hello Samudra,

Thank you, I will support you by reviewing both configurations.

Best,

Alec

0 Samudra Jampani 6 months ago in reply to Alec Saebeler

Prodigy 55 points

Hi sir,

I am trying to simulate the INA333 instrumentation amplifier, but I am not able to get the output as a replica of the input. It seems the circuit is not producing the expected result.

Please find the attached file(s) for your reference.
Kindly let me know if I have missed anything in the setup.

Best Regards,

Samudralankaiah.

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LMH6554: Request for Guidance on LMH6554LEE/NOPB Differential Amplifier Configuration