MSP430F6736A: Schematic Review to cross verify few Power Pins which are not available in 80-Pin package

SUMIT RANJAN

Expert 1985 points

Part Number: MSP430F6736A

Hi team,

I am working on power measurement project and using MCU having part number "MSP430F6736AIPNR" of 80-Pin package.

I can see there is difference in power Pin as well so wanted to verify our schematic with respect to power pin and its decoupling. Please cross check and share your valuable feedback on this.

Schematic_MSP430F6736AIPNR.pdf

over 3 years ago

0 Eddie LaCost over 3 years ago

TI__Mastermind 38590 points

Hello Sumit,

Please see my notes below.

Cvcore should be 470nF.
I don’t see DVCC connected to a source. We recommend connecting AVCC and DVCC together.
No source for AUXVCC3.
See note 2 of table 4-6 of the datasheet. The pins VDSYS and DVSYS must be connected externally on board for proper device operation.

0 SUMIT RANJAN over 3 years ago in reply to Eddie LaCost

Expert 1985 points

Hi Eddie

Thanks for your valuable feedback. I agree on all points and updated same in attached latest schematic. please check and review this.

MSP430_MCU schematic_Ti.pdf

One Query i have, I was checking reference schematic and i found that AUXVCC3 is not powered externally, it is just connected with VDSYS and DVSYS. Why is it not connected with external power source?

I am referring "TIDR106" schematic. Please clarify this.

0 Eddie LaCost over 3 years ago in reply to SUMIT RANJAN

TI__Mastermind 38590 points

Sumit,

See table 1 in the users guide for that design below. The design includes a jumper on AUXVCC3 which can be removed and external voltage applied if needed.

https://www.ti.com/lit/an/slaa517e/slaa517e.pdf

The schematic looks better now.

0 SUMIT RANJAN over 3 years ago in reply to Eddie LaCost

Expert 1985 points

Hi Eddie,

Do i need to conenct AUXVCC1 and AUXVCC2 with external voltage or just with cap it is ok?

As per table looks like there should be either external voltage or it should be with GND. This is confusion for me, can you please clarify more in details.

0 Eddie LaCost over 3 years ago in reply to SUMIT RANJAN

TI__Mastermind 38590 points

Sumit,

If you are using the AUXVCCx functionality, then you should use an external voltage. If not using AUXVCCx, it should be grounded. The reference design uses jumpers to allow for either functionality.

0 SUMIT RANJAN over 3 years ago in reply to Eddie LaCost

Expert 1985 points

Hi Eddie,

I am really confused. You mentioned AUXVCCx but in my design which i shared in that AUXVCC3 is only powered externally and rest two AUXVCC1 and AUXVCC2 is terminated with decap.

It is not grounded and nor used with external supply. I am not planning to use auxiliary power system so on AUXVCC1 and AUXVCC2 it should be connected with GND or with decap only?

0 SUMIT RANJAN over 3 years ago in reply to SUMIT RANJAN

Expert 1985 points

Hi Eddie,

Please update on this. And update on schematic, That is right or need some modification?

0 Eddie LaCost over 3 years ago in reply to SUMIT RANJAN

TI__Mastermind 38590 points

I recommend following the SLAA517E application report. If the AUX pins are unused, they should be grounded.

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MSP430F6736A: Schematic Review to cross verify few Power Pins which are not available in 80-Pin package