General
Review and verify the following for
the custom schematic design:
- Above sections, including
relevant application notes and FAQ links
- Pin attributes, signal
description, and electrical specifications
- Electrical characteristics
and additional available information
- A valid fixed supply source is connected to
(VDDSHV_CANUART, VDDSHV_MCU, VDDSHV0, VDDSHV1,
VDDSHV2, VDDSHV3) all the IO supply groups as per
the ROC
- A valid supply (that can be dynamically changed)
source is connected to are connected to VDDSHV4,
VDDSHV5, VDDSHV6 for AM62Ax IO supply group as per
the ROC
- Slew rate requirements for IO
supply rails are followed
- Internal LDO output pins have
the recommended capacitors connected (across CAP_VDDSn pin and VSS)
- Power sequence
recommendations as per the processor data sheet are followed
Schematics Review
Follow the below list for the custom
schematic design:
- Connection of the recommended
capacitor to CAP_VDDSn pins and VSS
- CAP_VDDSn capacitor package
(use the smallest possible (0201 or greater package possible which is
closest to 0201) package to minimize loop inductance)
- Voltage rating of the
capacitor selected for the capacitance value to be in the range 0.8 to 1.5μF
including aging, temperature and DC bias effect
- All IO supply rails have a
valid supply irrespective of the use of the IOs referenced to the IO supply
group
- Supply rails connected follow
the ROC
- Each CAP_VDDSn pin requires a
separate 1μF capacitor connected with respect to VSS (ground)
- Select CAP_VDDSn capacitor
with less the 1Ω ESR, keep the trace loop inductance to < 2.5nH
Additional
- For all supply rails, use a 0Ω
resistor or jumper for isolation or current measurement at the output of the
supply rails.
- When any of the VDDSHVx power
rails are sourced from the 3.3V supply, all IOs referenced to the IO supply
group VDDSHVx must operate at 3.3V levels. If a VDDSHVx power rail is sourced
from a 1.8V supply, all IOs referenced to the IO supply group VDDSHVx must
operate at 1.8V levels.
- Some interfaces span multiple
VDDSHVx IO supply groups, for example MMC2 and GPMC. When using one of the
interfaces, all VDDSHVx domains supporting a specific interface need to share
the same voltage source.
- Most processor IOs are not
fail-safe. Applying input voltage to the IOs while the corresponding IO power
domain (VDDSHVx) is off is not allowed or recommended.
- Verify all IO pins on each VDDSHVx (or
MCU_VDDSHVx) supply only support one voltage level.
- Follow the processor-specific SK
for implementation of ferrites and capacitors.