General
Review and verify the
following for the custom schematic design:
- Reviewed
above "Common checklist for all
sections" section of the user's guide.
- The
configured output voltage level and the current
sizing (rating) for the supply rails.
- Output
voltage feedback connection and feedback resistor
divider tolerance.
- Selected
discrete DC/DC supports active discharge.
- Discrete
DC/DC output slew rate meets the processor
requirements.
- Sequencing of the supply rails as per the processor
requirements.
- MCU_PORz
input (DC/DC PG output) slew rate and MCU_PORz input
L->H after all the supplies ramp.
- Voltage
rating of the selected capacitors considering
derating.
- Implementation of SD card interface IO supply
supporting UHS-I SD card.
- Implementation of VPP (eFuse programming)
supply.
- Naming of
the supply rails.
- Matching
of the Discrete DC/DC or Discrete LDO voltage
levels.
- Net name
matches (same name) for processor and attached
devices IO supplies.
Schematic
Review
Follow the list below for
the custom schematic design:
- The
resistor divider value including tolerance connected
to the feedback to generate the required output
supply voltage matches with the calculated value for
discrete DC/DC or LDO.
- DC/DC or
LDO outputs current sizing.
- Discrete
DC/DC or LDO PG outputs have the required pullup and
connects to other DC/DC or LDO EN for supply
sequencing.
- DC/DC or
LDO outputs slew rate matches the processor slew
rate requirements.
- MCU_PORz
input (DC/DC PG output) slew rate (connect through
discrete push-pull output type buffer) and L to H
delay (MCU_PORz input low hold time for clock
start-up and stabilization) implementation after all
the processor supplies ramp.
- MCU_PORz
input low hold time after supplies ramp, in case the
DC/DC PG output connects directly to the processor
MCU_PORz input.
- Implementation of VPP (eFuse programming) supply
including capacitors to support load current
transients and output enable (EN).
- Implementation of LDO for SD card interface IO
supply for supporting UHS-I SD card.
- Naming of
the supply rails (indicate configured output
voltage).
- Matching
of the Discrete DC/DC or Discrete LDO voltage levels
with the supply requirements for the processor and
attached devices.
- Voltage
rating of the selected capacitors considering
derating (> twice the worst-case applied voltage
is a commonly used guideline).
- Discrete
power device selection including output supply
voltage rails (operating voltage/amplitude) and
current rating, active discharge, provision to
enable, slew rate control, residual voltage
detection (Allow to power-up only when the supply
voltages are < 300mV after power-down).
Additional
- In case custom
board design power architecture is based on TI power, the
recommendation is to obtain a detailed review of the
implementation with the relevant business unit or product
line.
- A 0Ω resistor or
jumper is recommended at the output of the 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 add a zener at the output of discrete
DC/DC or discrete LDO when adjustable output type discrete
DC/DC or discrete LDO are used.