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 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