Trenz Electronic GmbH Support Forum

Trenz Electronic Products => Trenz Electronic FPGA Modules => Topic started by: xetnik on August 22, 2017, 04:29:53 PM

Title: Power outage when plugging in an SFP cable to TEBA0841
Post by: xetnik on August 22, 2017, 04:29:53 PM
Hi all,

I am using TE0741-160-2CF together with the TEBA0841. I set EN_GTPWR high on H22, connect the TX and RX pins to the Aurora 64B/66B standard design in Vivado and use the standard MGTCLK1 and SYSCLK as clock sources. After loading the bitstream and the SFP cable still _un_plugged the system runs fine. When I plug in the SFP cable there is directly a complete power outage/short circuit happening somewhere. The power LEDs on the USB Adapter TE0790-02 go out and connection is lost to the board. FPGA temperature is normal around 40C.

I am not familiar with this, is it in general forbidden to plug in an SFP connector while the system is under power (I guess not)?

Any hints on how to debug this issue?

BR
Title: Re: Power outage when plugging in an SFP cable to TEBA0841
Post by: JH on August 23, 2017, 08:52:15 AM
Hi,

normally it should work. Maybe your SFP transceiver module has a problem. Do you have a second one to test?
It can be also be a power supply problem. Is there some current limit set on your external power supply? Current increase, if MGT data transfer starts.

Br
John
Title: Re: Power outage when plugging in an SFP cable to TEBA0841
Post by: xetnik on August 23, 2017, 04:00:54 PM
Dear John,

Thanks for your reply. Unfortunately right now I don't have another one to test. I am currently only using the power supply over the USB Adapter TE0790-02 connected to my laptop. I guess this isn't sufficient then to power both the FPGA and SFP adapter board? Where do I need to apply another external power source?

BR

Title: Re: Power outage when plugging in an SFP cable to TEBA0841
Post by: JH on August 23, 2017, 04:28:53 PM
Hi,

TE0790 delivers appr.  100mA and should not used for power supply:
See also:

It's a little bit like a miracle, that it will be starts with TE0741.  So you must connect external 3.3V power supply on the 3.3V Pin of J17, J20 or J3.
See Schematic page 4:

br
John
Title: Re: Power outage when plugging in an SFP cable to TEBA0841
Post by: xetnik on August 23, 2017, 04:38:19 PM
Hi John,

Thanks for the help. I'm going to try this out.

BR