General
Review and verify the following for the custom
schematic design:
- Reviewed above "Common checklist for all sections" section of the
user's guide.
- Connection of processor core VDD_CORE and peripheral core VDDA_CORE_CSIRX0,
VDDA_CORE_USB, and VDDA_DDR_PLL0 supply rails.
- ROC, slew rate and voltage sequence requirements for processor core and
peripheral core supply rails.
- Connection of VDD_CORE and VDDR_CORE when VDD_CORE supply is 0.75V or
0.85V.
- Peripheral core supply filters.
- Connection of core supply when specific peripherals are not used.
- Connection of peripherals core supply VDDA_CORE_CSIRX0 (CSIRX0) when peripheral
is not used but the boundary scan function is required.
Schematic Review
Follow the below list for the custom schematic
design:
- The recommendation is to compare the
implementation of the bulk and decoupling
capacitors for the supply rails with SK schematic
implementation or refer PDN application note.
- The supply rail operating voltage connected to
processor core supplies follows the ROC.
- Recommended supply voltage 0.75V or 0.85V is applied to the processor core
VDD_CORE and peripheral core VDDA_CORE_CSIRX0, VDDA_CORE_USB, and VDDA_DDR_PLL0
(supported only on the AMC package) supply rails operating voltage.
- Processor core and peripheral core supply rails connected to the relevant
supply pins follow the recommended voltage sequence. Refer Power-Up
Sequencing – Supply / Signal Assignments section of the
processor-specific data sheet for sequencing the core supplies when, partial IO
low power mode is used and when partial IO low power mode is not used.
- Slew rate of the supply rail follows the data
sheet requirements.
- The potential applied to VDDR_CORE never
exceeds the potential applied to VDD_CORE +0.18V
during power-up or power-down. The sequencing
requires VDD_CORE to ramp up before VDDR_CORE and
ramp down after VDDR_CORE when VDD_CORE is
operating at 0.75V.
- The recommendation is to power VDD_CORE and
VDDR_CORE from the same source when the VDD_CORE
is operating at 0.85V.
- Ferrite filters are provided for peripheral
core supplies (CSI, USB, CANUART) as per the SK
schematic implementation.
- Connection of core supply when specific
peripherals are not used as per pin connectivity
requirements.
- Connection of core supply (VDDA_CORE_CSIRX0
for CSIRX0), when peripheral is not used but the
boundary scan function is required, follow data
sheet pin connectivity requirements. Ferrites and
bulk capacitors are optional for peripheral core
supplies.
Additional
- VDDA_DDR_PLL0 supply rail is supported only in the AMC package. The supply rail
is internally connected to VDD_CORE in the ALW package.
- The recommendation is to add a 0Ω resistor or
jumper for isolation or current measurement at the
PMIC DC/DC or LDO output for the core supply. The
recommendation is to add TPs for measurement. The
recommendation is to follow kelvin current sense
connection to connect the TPs. Choose the resistor
package based on the supply rail current and the
resistor current carrying capacity.
- Dynamic voltage scaling (DVS) of core supplies
is not supported (not recommended or
allowed).
- Changing the core voltage is not allowed after
the device is released from reset. If the core
supply is turned off, the recommendation is to
ramp down all the power rails as per the
power-down sequence and wait until all supply
rails decay below 300mV before turning on power.
- When USB driver is not initialized and the USB
calibration procedure does not happen, connecting
the supplies and leaving all of the USB pins for
USB0, USB1, or both is acceptable. Grounding the
USB supplies per pin connectivity requirements
when both USB interfaces are not used reduces
power when low power is a critical requirement.