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 (VDDSHV0, VDDSHV1) all the IO supply for IO groups as per the ROC
- A valid supply (that can be dynamically switched) source is connected to VDDSHV2, VDDSHV3, and VDDSHV4 as per the ROC of the processor-specific data sheet
- Slew rate requirements for IO supply rails for IO groups are followed
- Internal LDO output pins have the recommended capacitors connected (across CAP_VDDS_xxx pin and VSS)
- Power sequence recommendations as per the processor-specific data sheet are followed
Schematic Review
Follow the below list for the custom schematic design:
- Connection of the recommended capacitor to CAP_VDDS_xxx pins and VSS
- CAP_VDDS_xxx 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 effect of DC bias
- All IO supply rails for IO groups have a valid supply irrespective of the use of the IOs
- Supply rails connected follow the ROC
- Each CAP_VDDS_xxx pin requires a separate 1μF capacitor connected with respect to VSS (ground)
- Select CAP_VDDS_xxx capacitor with < 1Ω ESR, keep the trace loop inductance < 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. Choose the package of the resistor based on the supply rail current and the resistor current carrying capacitor.
- When any of the VDDSHVx power rails are sourced from the 3.3V supply, all IOs referenced to the VDDSHVx are required to operate at 3.3V IO level. If a VDDSHVx power rail is sourced from a 1.8V supply, all IOs referenced to the VDDSHVx are required to operate at 1.8V IO level.
- Some interfaces span over multiple VDDSHVx. When using any of the interfaces, all VDDSHVx domains supporting a specific interface are required to share the same voltage source.
- Most processor IOs are not fail-safe. Applying input voltage to the IOs while the corresponding VDDSHVx supply is off is not recommended or allowed.
- Verify all IO pins on each VDDSHVx only connects to a single voltage level.
- Follow the processor-specific EVM for implementation of ferrites and capacitors.
- Leaving VDDSHVx rail unconnected is not recommended. Connect the power pins to either 1.8V or 3.3V, depending on the use case and the ROC.