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ADIN1100 Media Converter without Controller

Category: Hardware


I have been using the EVAL-SPoE-KIT-AZ to test media conversion with SPoE.

I noticed on the LTC9111 Board there is an MCU installed. The circuit diagram says it's "Eval Purpose Components Only". However when I desoldered the MCU the media conversion no longer worked.

Looking into the circuit and datasheet of the ADIN1100 there are strapping options for using the PHY as a media converter without an MCU. Regarding the ADIN1200 it doesn't look like it works without the MCU.
Changing the resistors so it disables software power down mode gives me a feedback from the link LEDs but I cannot ping any device through the converter.

Is there something I am missing or is it not possible to assemble a media converter without using an MCU?

Thanks for your feedback.


  • Hi DerJan,

    The behavior you see is expected. The ADIN1100 is 10BASE-T1L, 10Mbit/sec full duplex. To work correctly as media converter, the ADIN1200 must also operate in 10Mbit/sec full duplex, and auto-negotiation is the only reliable and correct way to achieve it.

    So yes, a microcontroller is required for writing a few registers via MDIO to configure the ADIN1200 for auto-negotiation advertising 10Mbit full duplex. This option is not available via ADIN1200 hardware configuration / pin strap. Such configuration is required as there is no buffer for data in PHY to PHY back-back connection in media converter.



  • Hello Shazia,

    thanks for your answer.

    Looking through the hardware configuration pins of the ADIN1200 I found this table:

    If I get this right I can configure the ADIN1200 to operate in Auto Neg with 10 Mbps (Row Nr. 2). When taking a device and forcing it to be 10 Mbps Ethernet the signal the ADIN1200 receives should be 10 Mbps right?

    I thought this should solve the problem but it did not. What's the reason for that?

    Kind regards,


  • Hi Jan,

    To your point, row No.2 will configure the ADIN1200 to operate in autonegotiation with 10Mbps/ 100Mbps, HD/FD. The option to pin strap the ADIN1200 for 10Mit FD autoneg disabled will require the other side of the link to be configured the same, autoneg disabled 10Mbit FD. The devices usually have autoneg enabled, and if the autonegotiation fails, acc. to IEEE802.3 standard, the port then defaults to 10Mbit half duplex, and that creates a problem of collisions on the link and loosing packets. If one side of a link is set to autoneg and the other is set to forced, than only a half duplex link can be brought up.