AMIC110: Sneak current between 1.8V to 1.1V

Hi Koichiro,

Power sequencing is a system level concern where the designer must understand limitations of all on-board and all off-board attached devices.

Since this is not observed on the AMIC110 ICE but is on the customer board (per the attachment), and not observed on with AMIC110 otherwise, this is likely caused by a configuration of other components on the customer board.

Is inserting a level shifter an option on the 1.1V rail to block the leakage?

Regards,

Colin

Hi Colin,

I am not sure I fully understand your comment below. Could you clarify what does it mean exactly?

Colin Callaghan said:

and not observed on with AMIC110 otherwise,

And could you also explain a bit more about below option?
I am not familiar to use a level shifter to avoid current leakage. 

Colin Callaghan said:

Is inserting a level shifter an option on the 1.1V rail to block the leakage?

Thanks and regards,
Koichiro Tashiro

Hi Koichiro,

Koichiro Tashiro said:

I am not sure I fully understand your comment below. Could you clarify what does it mean exactly?

Colin Callaghan said:

and not observed on with AMIC110 otherwise,

I am referring to the xlsx attachment, in cell A3:

"The issue is observed on customer's board, but not on AMIC110 ICE."

Koichiro Tashiro said:

And could you also explain a bit more about below option?
I am not familiar to use a level shifter to avoid current leakage. 

Colin Callaghan said:

Is inserting a level shifter an option on the 1.1V rail to block the leakage?

The level shifter solution has been implemented by others to help block small amounts of leakage current issues in the past. Most of those issues are in the order of micro-watts while the leakage here is much larger and more like mili-watts.

Has the customer confirmed the software pullups/pull downs? This seems like something is being contended, where GND is expected but a signal is being pulled high.

Regards,

Colin

Hi Colin,

Thanks for your reply.
Regarding below comment, the signal showing ~200mV is 1.1V power rail itself. So software pulls are not possible.
And the power rail is connected to AMIC core supply only.

Colin Callaghan said:

Has the customer confirmed the software pullups/pull downs? This seems like something is being contended, where GND is expected but a signal is being pulled high.

Is there any case if some signals are pulled up with 1.8V, it will raise 1.1V power rail GND level?

Thanks and regards,
Koichiro Tashiro

Hi Koichiro,

Does the 1.1V power supply power any other component on the board aside from the AMIC110? If so we should confirm that there are no leakage paths in any of those other components.

And can you please confirm the topology of the CAP_VDD_RTC and RTC_KALDO_EN pins of AMIC110? Does it reflect the topology of the reference board, where 1v1 powers MPU, CORE and CAP_VDD_RTC? And RTC_KALDO_EN is pulled high to 1v8 (which disables the internal LDO)?

Regards,

Colin

Hi Colin,

I will send you the details of customer board power rails etc. in offline.
I was not able to find any suspicious point though.
Could you check them as well?

Thanks and regards,
Koichiro Tashiro