LMZM23600: Where is the top to measure Psi_JT?

Noriyuki Takahashi

Part Number: LMZM23600

Hi team,

Where is the top of LMZM23600 to measure Psi_JT?

I just want to make sure that the top center of package is measured to get Psi_JT like other packages according to JEDEC. Please see the attached.

Regards,

Noriyuki Takahashi3187.question.pptx

over 6 years ago

0 Jimmy Hua over 6 years ago

TI__Guru 50120 points

Hi Takahashi-san,

The Psi_JT spec can be found on page 5 of the datasheet. It is spec'd to be 3 deg C/W.

Regards,

Jimmy

0 Noriyuki Takahashi over 6 years ago in reply to Jimmy Hua

TI__Genius 10950 points

Jimmy,

My question is to know where is measured to get the temperature of top and calculate the junction temperature.

It is easy to understand it in case of SOIC package, because its top is totally flat. However, LMZM23600's surface is not flat. So we are not sure where should be measured to get the temperature of the top.

Regards,

Noriyuki Takahashi

0 Jimmy Hua over 6 years ago in reply to Noriyuki Takahashi

TI__Guru 50120 points

Hi Takahashi,

I would measure the temperature centered on the exposed inductor. During thermal characterization of this part I used an IR gun pointed at the exposed inductor to help create Figure 69.

Regards,

Jimmy

0 Noriyuki Takahashi over 6 years ago in reply to Jimmy Hua

TI__Genius 10950 points

Hi Jimmy

Please let me ask again.
You measured the temperature centered on the exposed inductor to get Figure 69.
How about Psi_JT? In this case, you measure the temperature centered on the exposed inductor to get it?

Regards,
Noriyuki Takahashi

0 Denislav Petkov over 6 years ago in reply to Noriyuki Takahashi

TI__Mastermind 19891 points

Hello Takahashi-san,
I believe the Psi_JT was measured in from the embedded die to the top of the laminate PCB.
Cheers,
Denislav

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LMZM23600: Where is the top to measure Psi_JT?