LS1043, VDDSENSE, GNDSENSE

[netzocep]

Hi, do I need to connect the SENSEVDD and SENSEGND Pins? How to terminate when unused? thanks

[netzocep]

Hi,

unfortunately I have no possibility to connect the pins on my voltage regulator and I have found various recommendations....

AN5012 from 2016 recommend "This pins should be left floating" if not used, 

and for LS1046

<https://community.nxp.com/t5/QorIQ/LS1046A-Inquiries-regarding-pin-termination/m-p/1154382/highlight...>

5) As I already wrote: "If not used could be left unconnected."

[mrudangshelat-13]

Hi @netzocep,

Kindly use the latest revision of document for your design which is available at the NXP site. And as per the latest revision design checklist, the pins should not be left floating. You can go through the LS1046A FRWY schematic design for further reference.

Regards,
Mrudang

[netzocep]

Dear Mrudang,

I knew the schematic, a Buck Regulator with a differential / Kelvin sense option is used.

You assume that it is absolutely necessary to use a  DC/DC Buck regulator for the core voltage with a differential sense amplifier?

regards

[mrudangshelat-13]

Hi @netzocep,

Refer to LS1046A FRWY design as it doesn't have the sense pin. Can you share the mfg part no. of the regulator that you intended to use?

Regards,
Mrudang

[netzocep]

Hi,

at the LS1046 FRWY design the part LTC7150S with a sense Pin is used (Vout-/ pin A6),

For my design with the LS1043 the LTC7150S is oversized (20Amps), I would like to use the 

the LT8642EV-1 (10Amps).

regards

[netzocep]

Hi, 

any news to my reply?

regards

[mrudangshelat-13]

Hi @netzocep,

Please connect the VDDSENSE to the VDD rail. Ensure the pin don't left floating.

Regards,
Mrudang

[netzocep]

Hi,

thanks, and GNDSENSE to GND rail?

regards

[mrudangshelat-13]

Hi @netzocep,

Yes, connect to GND.

Regards,
Mrudang

[mrudangshelat-13]

Hi @netzocep,

I am working on your case and I will get back to you once I have any progress.

I hope you understand

Regards,
Mrudang

[netzocep]

perfect

[mrudangshelat-13]

Hi @netzocep 

Refer to table#4 in AN5012 for the termination details of SENSEVDD & SENSEGND pins.

Regards,
Mrudang Shelat

[netzocep]

Hi,

I would like to use a DC/DC Buck without a differential sense amplifier, means "not used" Pins, table 4 / AN5012. Is it ok to float VDDSENSE and GNDSENSE, or do I need a DC/DC Buck with a differential sense amplifier?

regards

[mrudangshelat-13]

Hi @netzocep,

If not used then connect to regulator feedback as per the AN5012.

Regards,
Mrudang

[netzocep]

sorry, Is it ok to float VDDSENSE and GNDSENSE?, with the buck regulator I would like to use there is no possibility to connect these pins to the DC/DC Buck regulator feedback.

regards

[mrudangshelat-13]

Hi @netzocep,

These pins should not be left floating. I suggest you to follow the design checklist of LS1043A.

Regards,
Mrudang