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)
- 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 GPIO6
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 GPIO6 (High: Buck1/2/3 = 0.85V, Low/Floating: Buck1/2/3 = 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
- SD card IO voltage control
configuration pin connection (3.3V during start-up and switched to 1.8V),
verify the VSEL_SD (GPIO5) configuration based on SD card interface use
case
- Connection of SD card supply
enable SDCARD_EN (GPIO11, connects to the SD card load switch enable ANDing
logic output)
- PMIC nRSTOUT slew (pullup
value) when connected directly to processor MCU_PORz input (recommend using
a discrete push-pull output buffer)
- VPP supply (eFuse
programming) output control and addition of bulk and decoupling capacitors
considering load current transient and provision for isolation resistor for
testing the VPP enable timing
- Configuration of other
discrete DC/DC supplies and LDOs used along with the PMIC
- Connection of interrupt, EN,
sleep signals, and pulls for the IOs
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