A good PCB layout practice is to keep the analog and digital grounds separate, use a solid ground plane, and keep the high-frequency signals away from the analog signals. Additionally, use a common-mode choke or ferrite bead to filter the power supply lines.
Make sure to follow the power-up sequence specified in the datasheet, and ensure that the VCC and AVCC pins are decoupled with 0.1uF and 10uF capacitors, respectively. Also, configure the device by writing to the control registers according to the datasheet.
The maximum cable length supported by the MAX3490ECSA+T depends on the specific application and the type of cable used. However, as a general guideline, the device can support cable lengths up to 100 meters for Category 5e cables and up to 50 meters for Category 3 cables.
Use an oscilloscope to check the signal integrity on the transmit and receive pairs, and verify that the device is properly configured and powered up. Also, check the device's status registers to identify any error conditions.
Yes, the MAX3490ECSA+T can be used in a redundant or backup system. The device has a built-in switch that allows it to be used in a redundant configuration, and it also has a hot-swap capability that allows it to be replaced without interrupting the system operation.
MAX3490ECSA+T datasheet
by Maxim Integrated Products
