Tool/software:
Hi,Experts
My customer is designing a circuit with reference to the EVM board SK-AM68.
However, my customer is having trouble interpreting the CPU power supply
because there are discrepancies between the SK-AM68 circuit and the description in the datasheet.
In the SK-AM68 circuit,
VDD_MCU,
VDD_MCU_WAKE1,
VDDAR_MCU,
VDDAR_CORE,
VDDAR_CPU
are connected as the same supply.
On the other hand, the AM68 data sheet “JAJSQ12B - FEBRUARY 2023 - REVISED DECEMBER 2024” at
contains the following comment.
DataSheet
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Page 126 Notes
I. VDD_MCUs are digital voltage domains with a wide operating voltage range and can be grouped
with either VDDAR_MCU domains or VDD_CORE. In the MCU and Main Domain Coupling Power-Up Sequence,
VDD_MCUs can be grouped with VDD_COREs.
If VDD_MCU is grouped with VDD_CORE, VDD_MCU must ramp up from a common voltage source
with VDD_CORE of 0.8V at T2.
If VDDAR_MCU is not grouped with VDD_CORE, VDD_MCU must ramp up before T2.
In either case, the VDDAR supply must be ramped at T3.
Page 131 Notes
I. VDD_MCUs are digital voltage domains with a wide operating voltage range and can be grouped
with either VDDAR_MCU domains or VDD_CORE.
In the MCU and Main Domain Separate Power-Up Sequence, VDD_MCUs can be grouped with VDDAR_MCUs.
The VDD_MCU must ramp up before T2.
If VDDAR_MCU is not grouped with VDD_MCU, it must ramp up at T3.
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The VDD_MCU can be grouped with the VDDAR_MCU. In this case, it ramps up at T2.
However, VDDAR_MCU cannot be grouped with VDDAR_CORE and VDDAR_CPU
(because VDDAR_CORE and VDDAR_CPU ramp up at T3).
can be judged, but does it mean that the SK-AM68 circuit is wrong?
Best Regards
Hidekazu
