LM148QML: PCB Layout guidelines for Op-Amps

Links

Genius 14490 points

Part Number: LM148QML
Other Parts Discussed in Thread: LM148-N

Hi Team

Do you have reading materials that we can use for PCB layout guidelines regarding this OP-AMPS?

Best Regards,

William

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 325940 points

The LM148-N datasheet says:

As with most amplifiers, care should be taken lead dress, component placement and supply decoupling in order to ensure stability. For example, resistors from the output to an input should be placed with the body close to the input to minimize “pickup” and maximize the frequency of the feedback pole which capacitance from the input to ground creates.

Also see The basics: How to layout a PCB for an op amp.

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

TI__Mastermind 30760 points

Clemens once again beat me to the answer!

Hi Jiahui,

I'd recommend taking a look at the link that Clemens linked too. It's a good article that goes into the thought process behind how you should layout the board! Let us know if this helps you or if you have any further questions.

Best Regards,

Robert Clifton

0 Links over 4 years ago in reply to Clemens Ladisch

TI__Genius 14490 points

Hi Team

Regarding the link here in e2e forum:
The basics: How to layout a PCB for an op amp - Precision Hub - Archives - TI E2E support forums

It is not stated here regarding information about where the stray capacitances come from. Author understandably limited the info to the basics.

Can you provide more information regarding stray capacitance?

Have a great day!

Best Regards,

William

0 Links over 4 years ago in reply to Robert Clifton56

TI__Genius 14490 points

Hi Team

Best Regards,

William

0 Robert Clifton56 over 4 years ago in reply to Links

TI__Mastermind 30760 points

Hi William,

I understand now, you are looking for a more in depth analysis and understanding! I think How to trouble shoot Op Amp PCB layout issues with real world examples would be helpful. It goes more into depth of potential issues that you could see.

For more on how it effects the Op Amp I would recommend reading this document: Effect of Parasitic Capacitance in Op Amp Circuits.

Let me know if this is sufficient or if this is not quite what you were looking for!

Best Regards,

Robert Clifton

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LM148QML: PCB Layout guidelines for Op-Amps