ADIN1200 LED0 pull up

Hello Teli,

Thanks for your question. 

You are correct, the LED0 pin is referenced to AVDD_3P3 which is a 3.3V rail. This is to ensure sufficient voltage to drive an LED. 

The other MII interface pins are referenced to VDDIO, VDDIO can operate from 1.8V to 3.3V depending on use case. 

Question2: If you do not use LED0 as an LED function, then for strapping purposes, you still need to reference the pin to the AVDD_3P3 rail, to achieve MODE 4, is a pullup to AVDD_3P3. 

Question3: Yes, the I/O voltage of this pin will be referenced to 3.3V even with VDDIO = 1.8V. 

best regards,

Catherine.

Hello Catherine,

Thank you for your anwer.

Regarding to question2, could you tell me why we need to reference the pin to the VDDIO for MODE 4?  

I thought that I can connect the pin to VDDIO directly for MODE 4 if supplied voltage  is > 0.9V*VDDIO.

For MODE4,  do we need to reference the pin to the AVDD_3P3 even with VDDIO= 3.3V ?

Please let me know your advice.

Regads,

Teli

Hello Catherine

Please update this thread.

Regards,

Teli

Hi Teli,

The ADIN1200 uses the voltage level at the LED0 pin for hardware strapping during initialization. After this process, the pin reverts to its default function, driving the LED. However, if the LED0 pin is directly connected to a power source, such as 3.3V, a short circuit to the ground will occur whenever the LED0 pin is set to LOW (0V)

regards,

Mark