topic Re: i.MX6SoloX NVCC_RGMII voltage setup in i.MX Processors

i.MX6SoloX NVCC_RGMII voltage setup

tbrisebois — Thu, 30 Jul 2015 18:41:15 GMT

We are using the newer i.MX6SoloX device in our design and looking for some help on the NVCC_RGMII1/2 power groups supplies.

From what I read, these two groups are essentially powered by the PHY that is connected to the i.MX device. The operating range of NVCC_RGMII is given as 1.35V to 3.6V in table 10 of the IMX6SXIEC. However, there are three “modes” defined for RGMII: 1.5V, 1.8V and 2.5V. Is there anything that would prevent me from supplying 3.3V to this interface? This would make Ethernet connectivity much simpler, and eliminate the need for two separate voltage rails on this interface.

Thanks

Re: i.MX6SoloX NVCC_RGMII voltage setup

art — Fri, 31 Jul 2015 10:15:17 GMT

Typically, the RGMII Gigabit Ethernet PHY interface provides an analog voltage regulator (typically, installed on PHY IC) that makes the appropriate supply voltage for the PHY (and corresponding CPU interface) I/O signals. The typical values of this voltage (depending on implementation) are 1.5V, 1.8V or 2.5V. Powering the whole interface from 3.3V may get it out of spec. For example, please refer to the schematics of the i.MX6SoloX SABRE SD board, available on the Freescale web site:

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=RDIMX6SABREBRD&fpsp=1&tab=Design_Tools_Tab

Have a great day,
Artur

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Re: i.MX6SoloX NVCC_RGMII voltage setup

weidong_sun — Fri, 31 Jul 2015 12:17:45 GMT

Hi TB,

For RGMII powre, most of PHYs are 1.5V, 1.8V & 2.5V, so datasheet gives 3 kinds of voltage mode. due to the rating of RGMII is 3.6V, so if you use 3.3V for RGMII power, it is no problem.

Regards,

Weidong