Custom Carrier Board

1

I am working on a custom carrier board design and had the following queries regarding Power Selection Module.

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  1. What is the funtion of VDD_3V3_SPEKTRUM and VDD_3V3_SPEKTRUM_EN on the PSM?
  2. If I don’t need 3.3V anywhere on my board, can I omit the 5V to 3.3V Conversion done by MIC5332 on the PSM? Referenced from PSM Schematics given on github
  3. If I can omit, what should I do with the VDD_3V3_SPEKTRUM_EN pin connections for cube(PIN 19 of DF17 connector). Should I leave it floating?
  4. As per my understanding, VDD_3V3_SPEKTRUM is not connected to Cube but VDD_3V3_SPEKTRUM_EN is. Please correct if I am wrong.

Thank you in advance

2

Hello Vidya,

  1. VDD_3V3_SPEKTRUM connects to pin 1 of the 3pin connector named SPKT on the carrier board. So Spektrum DSM, DSM2 etc receivers connect to that port and Pin 1 provides the power to the receiver. VDD_3V3_SPEKTRUM_EN as the net name says is a signal that comes from the cube to enable this 3V3 output if you configure Spektrum as the receiver in the GUI.
  2. As the MIC5332 generates this 3V3, if you are not using Spektrum as the receiver, then it can omitted.
  3. As this signal is either a high to enable the output or low to turn off, in your case it will always be off. So it can be left floating or can be tied to GND with a 0E resistor.
  4. Yes, VDD_3V3_SPEKTRUM net is only connected on the 3pin SPKT connector apart from the ESD diode for protection.

If you share your schematic here or in PM, I can review it for you. Also I hope you have applied for a license for custom carrier board development on Github.