R-theta-JA (Junction to ambient thermal resistance) for ADSP-21565BSWZ8

Hi Mihir,

Please refer ENVIRONMENTAL CONDITIONS"(Page No: 88/102) in the ADSP-21565 datasheet linked below:
www.analog.com/.../adsp-21562-21563-21565-21566-21567-21569.pdf

Regards,
Divya.P

Hi Divya,

In the Environmental conditions page, R-theta-JA (Junction to ambient thermal resistance) value is not provided.

Even if, this methodology cannot predict the performance of the device, to get started we need some inital value of R-theta-JA.

Hi Mihir,

As mentioned in the datasheet under "ENVIRONMENTAL CONDITIONS", The ADSP-2156x processors are rated for performance over the temperature range specified in Operating Conditions. Application system thermal simulation is required for accurate temperature analysis. The thermal simulation must account for all specific 3D system design features, including, but not limited to other heat sources, use of heat sinks, use of thermal interface materials, and the system enclosure details. Thermal models of the package are available from Analog Devices under the Tools and Simulations tab of the product web page. The thermal model(s) are compatible with all major thermal simulation tools.

The thermal models are available in the web page under "Tools & Simulations", you have to import in to thermal software. The link for the ADSP-21565 "webpage" and "thermal models" is given below.
Webpage : www.analog.com/.../adsp-21565.html
Thermal models : www.analog.com/.../ctm-adsp-21562-21563-21565.pdml

Regards,
Divya.P

Hi,

I am also looking for below parameters:

1. R-theta-JC (Junction to top Case thermal resistance)

2. R-theta-JB (Junction to Board thermal resistance) / R-theta-JC (bot) (Junction to bottom Case thermal resistance)

Kindly provide the above mentioned data as early as possible.

Regards,

Mihir

Hi Mihir,

Apologies for the delay.

As mentioned earlier, the use of JEDEC qJA, qJC, or YJT thermal parameters for application system thermal estimates is not recommended as indicated in the JEDEC51 specifications.

Regards,
Divya.P

The thermal simulation is not feasible (or even possible) when selecting components, and with R-theta-JA value we (your customers) could make a ROUGH estimate, even it is not recommended.

Modeling a PCB without actually making the PCB is really difficult. I used (tried at least) flotherm and depending on the model i got junction temperatures of 120 to 300 C.

Also, in your model the exposed pad is higher than the LQFP leads so there will be airgap when using high resolution grid.

So please can you provide here the RJA (and others) value for LQFP and BGA packages?

With this value, it makes easier to get started with at least some confidence to Your product, that it does not smoke in our environment. There is a good excel to make the power estimate on different clock frequencies. We run the simulations when we have constructed the PCB layout and surrounding mechanics.

Hi Kimmo,

Can you please refer the below link.
https://www.analog.com/media/en/technical-documentation/product-information/assembly-considerations-for-umodule-bga-lga-package.pdf

We would suggest you to refer the application note(EE-414) which talks about "Estimating Power for ADSP-2156x SHARC+ Processors". Please find the link given below.
Https://www.analog.com/media/en/technical-documentation/application-notes/ee414.pdf

In the associated file furnished with this EE-note, there is a convenient power calculator tool. This tool allows users to obtain a total power profile by populating the cells in a spreadsheet with data found both in the processor datasheet and as a result of calculations specific to the intended application. The link is given below.
https://www.analog.com/media/en/technical-documentation/application-notes/ee414.zip

Regards,
Nandini C

Hi,

Thank you for the links, unfortunately they do not provide information i've been looking.

Hi Kimmo,

As we already mentioned, the use of JEDEC qJA, qJC, or YJT thermal parameters for application system thermal estimates is not recommended as indicated in the JEDEC51 specifications.

Can you please refer the application note(EE-449) which talks about "ADSP-21593/21594/ADSP-SC592/SC594 Processor Thermal Guidelines" from the given below.
https://www.analog.com/media/en/technical-documentation/application-notes/ee449v01.pdf

As mentioned in the processor data sheet, the application system thermal simulation is required for accurate temperature analysis. The thermal simulation must account for all specific 3D system design features, including, but not limited to other heat sources, use of heat sinks, use of thermal interface materials, and the system enclosure details. Thermal models of the package are available from Analog Devices product web page (under the Tools and Simulations tab). The thermal models are compatible with all major thermal simulation tools.

Regards,
Nandini C