Part Number: AM3356
Other Parts Discussed in Thread: TPS65218, TPS65218D0
I would like to Cross Verify and know the Actual power Consumption of AM3356 in RTC only Mode and current consumption of RTC Block during normal mode of operation.
As per Datasheet it says RTC i.e. VDDS_RTC consumes current of 5mA.
Kindly let me know whether my understanding is correct.
Hey Govardhan,
The VDDS_RTC 5mA current rating is the max consumption for power supply sizing.
For power consumption during RTC only mode, see attached slide on AM335x RTC power solutions.
To summarize: If using a discrete power solution with 1.8V connected to both RTC and 1.1V Internal LDO, power consumption is 18.8uA @ 1.8V = 34uA.
If using PMIC TPS65218 with separate 1.1V and 1.8V connections to AM335x RTC, the power consumption is 5.5uA @ 1.1V + 2.6uA @ 1.8V = 11uA.
For better efficiency and simplicity of design, the PMIC TPS65218 solution is recommended. 
-Sean
Hi,
I am using Super Cap instead of Coin Cell in my design.
Super Should power RTC only for around 5 Days.
Here is my design for reference .
Kindly Review.
Hi I've attached image of my RTC connection kindly Review.
Let me know if any additional information Required.
C256 Super Cap Backup Capacitor.
Govardhan,
I do not think this circuit will work to support RTC-only mode on AM335x due to voltage tolerance and power sequencing requirements.
1. A 1.8V LDO would be required to keep VDDS_RTC power supply within input voltage tolerance specifications.
2 VDDS_RTC and RTC_PWRONRSTn must be properly sequenced as described in the data sheet (below). 3.3V supply needs to be powered up after VDDS_RTC. I cannot tell in your schematic if +3V3 rail also powers the 3.3V IO pin on AM335x.
-Sean
