AM5718: Recommended pad configuration of unconnected pins

Sami Nurmenniemi

Part Number: AM5718

Hi,

From power consumption point of view, what is the recommended configuration for CTRL_CORE_PAD registers on unconnected pins?

Is it 0x0001000F, which would give following configuration:

Wake-up disabled
Fast slew
Input disabled
Pull up/down disabled
Default I/O timing
MUX mode = "Driver off" (Hi-Z)

Best Regards,

Sami

over 6 years ago

0 Biser Gatchev-XID over 6 years ago

TI__Guru**** 393215 points

Hi,

Please read section 2.5 in this document: www.ti.com/.../sprack7a.pdf

0 Sami Nurmenniemi over 6 years ago in reply to Biser Gatchev-XID

Prodigy 90 points

Hi Biser,

Thank you for the pointer, that section confirms the input should be disabled.

Datasheet of am5718 says (section 4.1.1 of www.ti.com/lit/ds/sprs957g/sprs957g.pdf): "All other unused signal balls with a Pad Configuration Register can be left unconnected with their internal pullup or pulldown resistor enabled."
- It sounds like "pull disabled" should not be used. But is pull-up or pull-down better for power consumption? Or is there no difference?

There is nothing mentioned about the mux mode. Is "Driver off" the recommended mode for unconnected pins?

Best Regards,
Sami

0 Biser Gatchev-XID over 6 years ago in reply to Sami Nurmenniemi

TI__Guru**** 393215 points

Internal pull resistors are very weak, and they will not have any significant effect on power consumption. Approximate values are 18kOhm @ 1.8V, resp. 33kOhm @ 3.3V. Driver should be off for unused pins.

0 Sami Nurmenniemi over 6 years ago in reply to Biser Gatchev-XID

Prodigy 90 points

Hi Biser,

Thank you. I'll configure unconnected pins as 0x0001000F:
- Input disabled
- Pull-down enabled
- Driver off (Hi-Z)

Best regards,
Sami

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AM5718: Recommended pad configuration of unconnected pins