LM2675: control loop parameters for LM2675

Jason Pearce

Part Number: LM2675

Hello

Would anyone be able to prove the values of GM1 and GM2, the control loop transconductance values as per the diagram on page 10 of the LM2675 data sheet in order to build an independent control model of the loop?

On the TPS series of regulators which are TI designs this is typically specified, but as the LM2675 appears to be an older part Nat Semis part, this information is missing.

Thanks in advance.

over 1 year ago

0 Joshua Austria over 1 year ago

TI__Genius 16915 points

Hi Jason,

Thank you for your question. We will look into and I will reach out to you soon with that information.

I appreciate your patience,

Joshua Austria

0 Jason Pearce over 1 year ago in reply to Joshua Austria

Prodigy 20 points

HI Joshua

thanks for the response. I'll wait to hear from you. Jason

0 Joshua Austria over 1 year ago in reply to Jason Pearce

TI__Genius 16915 points

Hi Jason,

This is an old part and it is proving a little challenging to find information about it. I will keep looking and give you an update next week.

Thank you for your patience

Joshua Austria

0 Jason Pearce over 1 year ago in reply to Joshua Austria

Prodigy 20 points

Hi Joshua

this doesn't surprise me: it came from Nat Semis which TI took over in the 2000's, so the information is archived somewhere. By the looks of it the data sheet hasn't changed much in 20 years. Thanks for your help.

Jason

0 Frank De Stasi over 1 year ago in reply to Jason Pearce

TI__Guru 68295 points

Hello

As Joshua mentioned, we would not be able to find the exact values for the parameters

you wish.

However, as a starting point you can use 1mS for both Gm1 and Gm2.

If you are building a loop model for this device, you can start with the above values

and adjust as needed to match your bench results.

Keep in mind that all of the values shown in the data sheet will have some

natural variation between different samples of device and with temperature.

Thanks

0 Jason Pearce over 1 year ago in reply to Frank De Stasi

Prodigy 20 points

Frank/Joshua

thanks for your input. I appreciate with the history and age of the device how difficult getting the requested information is . I'll take your suggestions and work from there. If this doesn't work I'll reopen the case. Thanks for your input.

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LM2675: control loop parameters for LM2675