SN74AVCH8T245 - Can I use this translator to support RGMII?

Bhavya,

That amount of current draw through the VCCB pin (92.4 mA) is within the acceptable limits of the SN74AVCH8T245 (100 mA). However, you mentioned that you intend to operate the device at a frequency of 250 MHz, which is not supported. The maximum supported clock frequency is 160 MHz.

Do you need 250 MHz operation?

Best Regards,
Nirav

Bhavya,

I read the RGMII Version 2.0 specfication. I do not believe that the data channels would operate at 250 MHz if the clock channel operates at 125 MHz. Instead, the data channels would operate at 250 *Mbps* (or 125 MHz as expressed in frequency).

Clock frequency = Number of cycles per second
Bit Rate = Number of bits per second
One clock cycle carries two bits (Positive Bit, Negative Bit)

This means that Bit Rate = 2 * Clock Frequency

The timing diagram below is taken from the RGMII specification (text in green and red is my addition):

 
TXC is the transmit reference clock. It operates at a maximum frequency of 125 MHz. This corresponds to a maximum bitrate of 250 Mbps (125 M cycles/second)*(2 bits/cycle).

TXD is the group of 4 data channels. Notice that there is one bit transmitted with the rising edge of TXC, and one bit transmited with the falling edge of TXC. So in one clock cycle, TXD also transmits 2 bits. This is identical to TXC.

In short, you can use the SN74AVCH8T245 to support the maximum data rates in RGMII.

Best Regards,
Nirav