TMS320C6748: Inquiry about the Power estimation spreadsheet.

Takayuki Miyazaki

Part Number: TMS320C6748

Hi team,

I received the inquiry about the Power estimation spreadsheet(www.ti.com/.../sprabf9 ). Since customer plans to use TMS320C6748 with 456MHz frequency, customer is considering to set CVDD=1.3V. However, customer is not sure how customer should set PLL0/1_VDDA and USB_CVDD to 1.2V. I don't believe customer needs to set those supply to 1.2V. I believe customer would like to know the reason why customer does not need to set those supply terminals in detail.

can I have Expert's advice/comments on this inquiry, please?

Best regards,

Miyazaki

over 3 years ago

+1 Colin Callaghan over 3 years ago

TI__Expert 8255 points

Hi Miyazaki,

Many of the 1.2V supplies are coupled to analog inputs, unrelated to the 1.3V VDD_CORE (for 456MHz configuration). For example the oscillator circuits are calibrated at 1.2V.

Likewise the PLL0/1 are analog IPs which are recommended to be coupled to 1.2V supplies. Same with the USB_CVDD.

The maximum voltage specified in the data manual for the signals you mentioned are listed at 1.32V. By operating at 1.3V the customer would be providing exceptionally low margin, especially across temperature conditions.

TI recommends the three signals that you inquired about should be coupled to 1.2V, not 1.3V supplies.

Regards,

Colin

0 Takayuki Miyazaki over 3 years ago in reply to Colin Callaghan

TI__Genius 10120 points

Hi Colin,

Thank you for your clarification and advices.

Best regards,

Miyazaki

0 Takayuki Miyazaki over 3 years ago in reply to Colin Callaghan

TI__Genius 10120 points

Hi Colin,

Please allow me to confirm it a little bit. Regarding Power estimation spreadsheet, there is not configuration for those analog power in spreadsheet. this reason is that TI recommends the three power terminals should be coupled to 1.2V and this spreadsheet calculates power value without analog configuration. Is that correct?

Best regards,

Miyazaki

0 Colin Callaghan over 3 years ago in reply to Takayuki Miyazaki

TI__Expert 8255 points

Hi Miyazaki,

Can you please send me the link to the power estimation tool you are using? I do not see it listed on the product page:

https://www.ti.com/product/TMS320C6748#all

In many PETs I see the VDDA_1v8 supply listed, which is typically an analog supply. Your observation is curious to me.

Regards,

Colin

0 Takayuki Miyazaki over 3 years ago in reply to Colin Callaghan

TI__Genius 10120 points

Hi Colin,

I'm sorry for my late reply.

There is TMS320C6748/46/42 power consumption summary( https://www.ti.com/lit/pdf/sprabf9 ) in product page. This document describes URL of PET ( : http://www.ti.com/lit/zip/sprabf9 ).

Thank you for your help and best regards,

Miyazaki

0 Colin Callaghan over 3 years ago in reply to Takayuki Miyazaki

TI__Expert 8255 points

Hi Takayuki,

Thank you very much for correcting me on the PET link!

After reviewing the PET, I agree with your understanding:

" there is not configuration for those analog power in spreadsheet. this reason is that TI recommends the three power terminals should be coupled to 1.2V and this spreadsheet calculates power value without analog configuration. Is that correct?"

I share the same understanding, that the 1.2V supply is fixed for the RAM module and other analog inputs. The most power-consuming component of the RVDD supply will be the the EMIF/DDR2 "Modules", which are User-Defined in cells F60 and F72 of the PET.

Regards,

Colin

0 Takayuki Miyazaki over 3 years ago in reply to Colin Callaghan

TI__Genius 10120 points

Hi Colin,

Thank you for your clarification.

I appreciate your help.

Best regards,

Miyazaki

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TMS320C6748: Inquiry about the Power estimation spreadsheet.