Power
PRELIMINARY INFORMATION
Jetson Orin NX Series and Jetson Orin Nano Series DG-10931-001_v1.1 | 17
POWER_EN
POWER_EN is a level active signal. When high, the system powers on or stays on. When low,
the system powers down or stays off.
SYS_RESET*
SYS_RESET* is bidirectional. The signal is controlled by the Power Sequencer or PMIC
during power-on and power-off. When the system is powered on, SYS_RESET* can be driven
by the carrier board to reset the SoC and QSPI boot device. This will not result in a full
system power cycle.
SYS_RESET* is not asserted externally during the power-down sequence. When POWER_EN is
de-asserted, the Power Sequencer or PMIC performs a power down sequence which
includes asserting SYS_RESET*.
SHUTDOWN_REQ*
SHUTDOWN_REQ* is driven active (low) by the module if the system must be shut down, due
to a software shutdown request, over-temperature event, undervoltage event, or other
faults. The power control logic on the carrier board must drive POWER_EN inactive (low) if
SHUTDOWN_REQ* is asserted.
SHUTDOWN_REQ* is not driven during power-on. It is pulled up to the VDD_IN supply, so stays
inactive. If the system is on and reset is driven low, the Power Sequencer or PMIC will
initiate a full power cycle and start the power-on sequence. Again, SHUTDOWN_REQ* is not
asserted. SHUTDOWN_REQ* will only go low when the module determines the system needs
to shut down.
SHUTDOWN_REQ* comes from a latch on module and is cleared when POWER_EN goes low.
If SHUTDOWN_REQ* is asserted, the carrier board must de-assert POWER_EN as soon as
possible.
Power Rail Discharge
To satisfy the power down sequencing requirement and prevent unwanted back drive from the
carrier board to the module, the following must be true:
The carrier board 3.3V power supply that powers any module I/O must be off within 1.5 ms
of SYS_RESET* assertion.
The 1.8V power supply that powers any module I/O must be off within 4 ms.
The power rails should be fully discharged before attempting to power back up.
Module ID
To support both legacy modules that take 5V only on VDD_IN as well as the wide range that
advanced modules can support (5V-20V) on VDD_IN, one of the original SODIMM GND pins (Pin
217) is re-tasked as a module ID pin. Legacy modules will have this pin tied to GND. Advanced
modules will have this pin floating. A pull-up is required on the carrier board on Pin 217 (GND
or module ID) if it will support the wide range VDD_IN input voltage. This pull-up will cause the
module ID level to be high if an advanced module is installed. The module ID pin level should
be used on the carrier board to determine if only 5V is supplied to VDD_IN (legacy module) or
the full advanced module VDD_IN range.
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