Questions tagged [lan8720]

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LAN8720 50Mhz clock: 33R termination/adaptation resistors

I'm trying to understand the function of these three 33R ohms resistors. The full schematic is here: Schematic I can understand the objective of R14 and R12: Split the clock and adapting it, but what ...
0
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1answer
139 views

Problem with ferrite bead - reduces power supply voltage

I built my own board with a LAN8720 chip but I can't get it to work. I found out that the ferrite bead I used only outputs ~1.4V from 3.3V input, which is way too low. I used some guidelines and other ...
1
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1answer
153 views

Crystal Oscillator for STM32F407 with LAN8720

I'm planning to build a custom board with STM32F407 chip for a system where I also need Ethernet connectivity. I'm planning to connect this board to a LAN8720 with breakout board from Smart ...
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1answer
32 views

Identification of Pin1 on LAN8720A 24SQFN package

can anybody help me identify which is pin 1 please? - which corner and side is pin 1? I find the data sheet and the actual picture confusing between the Datasheet and the device
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2answers
239 views

Inverting REFCLOCK of Ethernet PHY

A few years ago I had to design a board that uses the NXP LPC1769 MCU and had Ethernet connectivity. I was in need of a PHY chip and the LAN8720 was choosen. During design however, I noticed that NXP ...
12
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2answers
9k views

STM32F407 + LAN8720A + lwIP + FreeRTOS = No received Ethernet frames

I'm trying to bring up a PCB that uses an STM32F407 and LAN8720A Ethernet PHY, and I can't seem to receive any Ethernet frames — even though I have no problem transmitting frames. Hardware setup I ...