Questions Regarding Jetson Xavier 8GB Module and uncontrolled power down

Hi,

We are developing Carrier board for Jetson Xavier 8GB module. The below are the quires,

1.We need two SATA ports in our application and we are planning to interface module with 88SE9182 IC using PCIEx2 (UPHY9 and UPHY 8) to fulfill the requirement. Will this work?

  1. We need 2 Giga bit Ethernet ports. Since one Gb Ethernet(RGMII) is available from the module, we want to use WGI210IT IC to get one more port and for this we want to use PCIex1 (UPHY7), Will this work?

  2. We want to use SAM-TECH SEAM connectors(Differential impedance 100 ohms) for interconnection between carrier board and IO board. CSI,USB3.1 , DP/HDMI and MDI signals will be routed through this connector. Since the 699 MOLEX connector (2048430001 , 92 ohms differential impedance) used for these signals on the jetson module, will it be a problem if we route these signals through SAM-TECH SEAM connector.

  3. In OEM Product design guide trace impedance’s are given for all interfaces along with tolerance. Is it OK, if we design trace impedance’s with in the given tolerances.

  4. We want to use XR17V532(PCIe to UART) IC to get more UART ports. Will there be any problems with this?

  5. Can I order NVIDIA jetson evaluation kit with Jeston xavier 8GB module, please provide part number?

7.During uncontrolled power down, how does the Jetson xavier module behave. Does the module got internal capacitors or hold up circuit to maintain the internal rails for safe shutdown. From the OEM design guide, I came to know that the time required is 10 milli seconds after the VDDIN_PWR_BAD_N goes low.After VDDIN_PWR_BAD signal asserts to low (Due to loss of input), Should i maintain the rail voltage for 10 milli seconds in order to allow the safe shutdown?

Thanks,
M.J.K.Govind.

  1. For #1 & #2, it is OK to use the UPHYs, but a bridge of PCIe to SATA or RGMII is necessary.

  2. For #3 & #4, it is OK since there is 15% tolerance on impedance request.

  3. For #5, sure if it is standard PCIe port, it depends on the bridge IC not Xavier.

  4. For #6, please contact local vendor first and declaring 8GB should be workable.

  5. For #7, no need to do additional things as there is corresponding design in module for this.

Hi Trumany,

Thanks for the reply, Can you just give more clarity on point number 7.

Right now we are planning to implement hold up capacitors to maintain the HV and MV lines for 20 milli seconds during input power removal.

From your reply what i understood is,
Jetson xavier moudle has got internal power management circuit (May be with some hold up capacitors), which will hold the internal power supply rails during input power removal for safe shutdown. So no need to implement the external hold up capacitors. Even though the input power is removed , jetson module will do the safe shutdown.

Please correct me if i am wrong.

Just realize that you might not totally follow dev kit carrier design, if so, hold up caps are better for module to finish uncontrolled power down, and 20ms is OK.

Thank you ,

Since we are making our own carrier board, we will provide hold up capacitors to hold the HV and MV rails for 20 milli seconds during Uncontrolled power down.

Can you provide the lower voltage limits during uncontrolled power down.

The below are my assumptions,

HV shall be more than or equal to 9 Volts DC during uncontrolled shutdown(20 milli seconds of time).
MV shall be more than or equal to 2.9 Volts DC during uncontrolled shutdown(20 milli seconds of time).

Only monitor HV to > 8.04V, you can find the design in ‘power loss detection’ page of carrier board.