DP83849IF: SD level required for SFP detection

Sreekesh

Part Number: DP83849IF

Hi,

I am using DP83849IF to communicate using SFP transceiver. The SD pin on SFP transceiver is internally connected to ground.

I wanted to know what is the type of signalling used in pin 20 and pin 42 (FXSD_A and FXSD_B). What is the voltage level required on this pin when SFP is connected?

Regards,

Sreekesh.

over 5 years ago

0 Nikhil Menon over 5 years ago

TI__Genius 11725 points

Hi Sreekesh,

In FX mode, pin types are PECL. You may refer to the reference design in the "Design and development" tab of the product folder for a connection diagram.

Thank you,

Nikhil

0 Sreekesh over 5 years ago in reply to Nikhil Menon

Prodigy 30 points

Hi Nikhil,

The reference diagram shows HFBR-5803 transceiver which has inbuilt SD level generator. But the transceiver I am using, has SD pin connected to ground.

Could you confirm what are the PECL voltage levels required in FXSD_A and FXSD_B pins when SFP is connected and when its disconnected?.

Regards,

Sreekesh.

0 Nikhil Menon over 5 years ago in reply to Sreekesh

TI__Genius 11725 points

Hi Sreekesh,

You may refer to the following app note for interfacing between levels: https://www.ti.com/lit/an/slla120/slla120.pdf.

Exact voltage levels are not characterized, but we satisfy the Voh and Vol requirements. The voltage levels for PECL and LVPECL are different, but the logic is the same.

Thank you,

Nikhil

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DP83849IF: SD level required for SFP detection