General
Review and verify the following for the custom
schematic design:
- Above sections, including relevant application notes and
FAQ links
- PMIC
selection (orderable part number of NVM revision)
based on the DDR configuration (LPDDR4, DDR4)
- Addition of required input and output capacitors
including values, feedback configuration, and pin
connections
- Voltage rating of the selected capacitors considering
derating (> twice the worst-case applied voltage
is a commonly used guideline)
- Configuration of the recommended PMIC control and IO
signals including control of load switch or DC/DC to
sequence the processor IO supply sequence
- Naming of the supply rails (indicate configured output
voltage level)
- Matching of the PMIC voltage levels with the supply
requirements for the processor and attached
devices
- Net name matches (same name) for processor and attached
devices IO supplies
- Connections with the processor to support low-power
modes (when low-power modes are used)
Schematic Review
Follow the below list for the custom schematic
design:
- Compare the custom PMIC implementation with the EVM
schematic implementation for capacitors and values,
IOs connections, and Buck output feedback
connection
- Processor to PMIC and PMIC to processor IO interface
connections
- Connection of the required control signals for processor
IO supply sequencing (load switch EN for processor
and attached device IO supply output voltage slew
rate control)
- Processor and PMIC I2C interface used versus recommend,
considering the use case
- SD card IO voltage (using internal LDO) control
configuration pin connection (3.3V during processor
or board reset and switched to 1.8V)
- PMIC nRSTOUT slew (pullup value) when connected directly
to processor PORz (and RTC_PORz) input (recommend
using a discrete push-pull output buffer)
- Connection of interrupt, MODE/STBY, and EN/PB/VSENSE
signals
- Configuration of other discrete DC/DC supplies and LDOs
used along with the PMIC
- VPP supply (eFuse programming) external LDO
implementation, output control and addition of bulk
and decoupling capacitors considering load current
transient and provision for isolation resistor for
testing the VPP enable timing
- Connection of the required pulls for the PMIC IOs
- PMIC IO connected to processor RTC_PORz when configured
for low-power mode
Additional
- In case the power
architecture is based on TI PMIC, obtain a review of the
implementation done with the PMIC business unit or product
line.
- A 0Ω resistor or
jumper is recommended at the output of the supply rails
(Buck, LDO) for isolation or current measurement for the
initial board build. Select resistors that are rated for the
supply rail current
- Show the PMIC
input bulk capacitors connection for buck inputs and VSYS
separately and near to each of the pin separately for ease
of placement and routing.
- Follow the EVM implementation
- Reviewed and followed the FAQ related to residual voltage.