General
Review and verify the
following for the custom schematic design:
- The
sections above, including relevant application notes
and FAQ links
- PMIC
selection (orderable part number)
- PMIC
checklist for 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
- Provision
to configure core voltage using GPIO3
- Connection of analog inputs to PMIC ADC inputs
GPIO4 or GPIO5
Schematic Review
Follow the below list for the custom schematic
design:
- Compare
the custom PMIC implementation with the SK schematic
implementation for capacitors and values, IOs
connections, and DC/DC output feedback
connection
- Core
voltage configuration using GPIO3 (BUCK1,2 High:
0.85V, Low/Floating: 0.75V), VDD_CORE and VDDR_CORE
sequencing, and provision for alternate core voltage
configuration
- 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 voltage and
slew rate control)
- Processor
and PMIC I2C interface used versus recommend,
considering the use case
- PMIC
nRSTOUT slew (pullup value) when connected directly
to processor MCU_PORz input (recommend using a
discrete push-pull output buffer)
- 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
- External
Implementation of SD card supply supporting UHS-I
speed and eFuse programming VPP supply
- Connection of interrupt, EN/PB/VSESNSE and sleep
signals and pulls for the IOs
- Connection of analog inputs and input range for
GPIO4 or GPIO5
Additional
- For power
architectures based on a TI PMIC, get a detailed review of
the implementation with the PMIC BU/PL
- A 0Ω resistor or
jumper is recommended at the output of the supply rails for
isolation or current measurement for the initial board
build
- Show the PMIC
input bulk capacitors connection for DC/DC inputs and VSYS
separately and near to the pins for ease of placement and
routing