General
Review and verify the
following for the custom schematic design:
- Reviewed above "Common checklist for all
sections" section of the user's guide
- Selection of PMIC (OPN) based on the input supply and
the required output voltages (core voltage, IO
voltage and DDRSS voltage configuration)
- PMIC checklist for addition of required input and output
capacitors including values, feedback connection,
and pin connections
- Voltage rating of the selected capacitors considering
voltage derating
- Connection of the PMIC buck output feedback (after the
output bulk capacitor)
- Configuration of the recommended PMIC control and IO
signals
- Connection of the required control signals for processor
IO supply sequencing (load switch)
- Processor I2C interface instance used to interface with
the PMIC
- Processor to PMIC, and PMIC to processor IO interface
connections
- Connection of PMIC power good signal to processor
PORz (through discrete buffer or directly, pullup
(adjust resistor value based on the measured
slew))
- Connection of PMIC IO output to processor RTC_PORz when
RTC + IO + DDR low power mode is implemented
- Naming of the supply rails (indicating configured output
voltage level)
- Provision for isolating the PMIC output voltages for
current measure or testing
- Net name matches (same name) for processor and attached
devices IO supplies
- Connection of interrupt, MODE/RESET, and EN/PB/VSENSE
signals and connection of the required pulls for the
PMIC IOs
Schematic
Review
Follow the below list for
the custom schematic design:
- Configuration of the PMIC output to match the
processor and attached devices IO supply operating
voltages as per the custom board requirements
- The
custom board PMIC implementation with the EVM
schematic implementation for capacitors quantity,
size and values, IOs connection
- Connection of the PMIC buck output feedback (tie
the feedback after the output bulk capacitors)
- PMIC
nRSTOUT0 slew (pullup value) when connected directly
to processor PORz input (recommend using a discrete
push-pull output type buffer)
- Connection of the required control signals for
processor IO supply sequencing (load switch EN for
processor and attached device IO supply voltage and
provision for load switch output voltage slew rate
control using external capacitor)
- Voltage
rating of the selected capacitors considering
derating (> twice the worst-case applied voltage
is a commonly used guideline)
- Matching
of the PMIC output voltage level with the supply
requirements for the processor and attached devices
(based on the OPN)
- Processor
I2C instance used to interface to PMIC (Follow EVM
or review the required I2C instance based on the use
case)
- Configuration of discrete DC/DC outputs and LDOs
used along with the PMIC to generate additional
supply rails
- External
LDO implementation for generating VPP supply (eFuse
programming), LDO output enable (EN) control,
addition of bulk and decoupling capacitors
considering load current transient and provision for
isolation resistor for testing the VPP supply output
enable timing
Additional
- In case custom
board design power architecture is based on TI PMIC, the
recommendation is to obtain a detailed review of the
implementation done with the PMIC team (business unit or
product line).
- A 0Ω resistor or
jumper is recommended at the output of the PMIC and discrete
DC/DC, LDO for isolation or current measurement for the
initial board build. The recommendation is to add TPs for
measurement. The recommendation is to follow kelvin current
sense connection for connecting TPs to 0Ω resistor or
jumper.
- The
recommendation is to connect the feedback for the PMIC buck
output after the bulk capacitor. The recommendation is to
connect the feedback to make sure the removal of the 0Ω
resistor does not affect the PMIC operation (connect on the
PMIC side of the resistor).
- The
recommendation is to show the PMIC input bulk capacitors for
buck (DC/DC) inputs and VSYS separately and near to each of
the pin for ease of placement and routing.
- The
recommendation is to review and follow the FAQs related to
residual voltage.
- In case a non-TI
PMIC is used, the recommendation for custom board designers
is to review and follow the relevant processor collaterals
including the processor-specific data sheet and Maximum
Current Ratings application note. The
recommendation is to review the Recommended Operating
Conditions, Supply Slew Rate
Requirements, PORz Timing Requirements,
Power-Up Sequencing and Power-Down Sequencing
sections of the processor-specific data sheet and confirm
the selected PMIC based power architecture supports the
above requirements and residual voltage (RV) check.