General
- Review Section 1.1.4.1 of the user's guide.
- Connection of processor core VDD_CORE and
peripheral core VDDA_CORE_CSI_DSI,
VDDA_CORE_DSI_CLK, VDDA_CORE_USB and VDDA_DDR_PLL0
supply rails.
- VDD_MMC0 (pin 1K3, renamed as VDDR_CORE from SR1.2) and VDDA_0P85_DLL_MMC0 (pin
1J1, named as VDDR_CORE from SR1.2) supply rail.
- 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.
- Connection of VDD_MMC0 and VDDA_0P85_DLL_MMC0.
- Peripheral core supply filters.
- Connection of core supply when specific
peripherals are not used.
- Connection of peripherals core supply
VDDA_CORE_CSI_DSI, VDDA_CORE_DSI_CLK (CSIRX0 and
DSITX0) 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_CSI_DSI,
VDDA_CORE_DSI_CLK, VDDA_CORE_USB and VDDA_DDR_PLL0
supply rails operating voltage.
- VDD_MMC0 (pin 1K3, will be renamed as VDDR_CORE from SR1.2) and
VDDA_0P85_DLL_MMC0 (pin 1J1, will be named as VDDR_CORE from SR1.2) supply
rail operating voltage supported is a fixed 0.85V
- Connection of VDD_MMC0 and VDDA_0P85_DLL_MMC0
to the same source that is sourcing the VDDR_CORE.
- 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_DSI, USB, CANUART) as per the
SK schematic implementation.
- Connection of core supplies VDDA_CORE_CSI_DSI
VDDA_CORE_DSI_CLK (CSIRX0 and DSITX0), when
specific peripherals are not used as per pin
connectivity requirements.
- Connection of core supplies VDDA_CORE_CSI_DSI
VDDA_CORE_DSI_CLK (CSIRX0 and DSITX0), when
peripheral is not used but the boundary scan
function is required, as per pin connectivity
requirements. Ferrites and bulk capacitors are
optional for peripheral core supplies.
Additional
- 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.