Reference Ethernet clock

AFZ — Tue, 13 Jul 2021 15:41:54 GMT

Hi,

i am using LPC2388FBD144,551 mcu.

The pin NO 126 of mcu "ENET_REF_CLK" is being used for ethernet clock reference.

i am using 50MHz oscillator for ethernet clock and on the other side i am connecting same oscillator PAD to pin 126 of mcu.

due to mechnical reasons and board component density i cannot place mcu and ethernet block close to each other. oscillator 50 MHz is near to ethernet block but the trace length of 50MHz reference clock connecting to mcu is very long. > 50mm

can you please suggest some solution ?

Thanks

Regards

Re: Reference Ethernet clock

xiangjun_rong — Wed, 14 Jul 2021 06:24:45 GMT

Hi, Afzal,

The trace length of 50MHz Enet_REF_CLK signal is greater than 5CM, if you use a 4 layer board(top/bottom are signal layers, the VDD/GND are power layers), i think it is okay. If you develop two layers board, I suggest you paste copper on the opposite side of the Enet_REF_CLK signal.

Anyway, 4 layer board is recommended.

Hope it can help you

XiangJun Rong

topic Re: Reference Ethernet clock in LPC Microcontrollers

Reference Ethernet clock

Re: Reference Ethernet clock