SN65LVCP114: USE SN65LVCP114 to transport 100Mbps Ethernet signal met rise time and fall time issues.

RogerZ

Part Number: SN65LVCP114

Dear All:

Please help to check below issues with SN65LVCP114:

we have used this device as a 100Mbps ethernet port switch, The system structure shown below:

100Mbps Ethernet Signal - > | AINP0(pin) AINN0(pin) ------(SN65LVCP114) ----COUTP0(pin) COUTN0(pin) | ---> Ethernet Transformer

1: our input signal to SN65LVCP114 as below:

input signal Rise Time = 3.708ns (3ns <= Rise Time <= 5ns)

input signal Fall Time = 4.088ns (3ns <= Fall Time <= 5ns)

2: our out signal from SN65LVCP114 as below:

Rise Time = 1.324ns (3ns <= Rise Time <= 5ns)

Fall Time = 4.925ns (3ns <= Fall Time <= 5ns)

3: Our device has config by I/O set which shown below:

After we check the output signal, We find the rise time of output has bing reduced(3.078 ns to 1.324 ns) by SN65LVCP114 and fall time of output has bing pulled longer (4.088 ns to 4.925 ns), It cased our 100Mbps communication loss data packages , So we know to get a recommend SN65LVCP114 config data for 100Mbps application from e2e.ti.com, So please help to check this issues!!

over 8 years ago

0 RogerZ over 8 years ago

Intellectual 295 points

The input signal has bing tested very close by SN65LVCP114 AINP0 and AINN0 pins

0 Lee Sledjeski over 8 years ago

TI__Mastermind 43795 points

Hi Roger,

It would help me to understand why you would use the LVCP114 for 100 Mbps ethernet. This device is optimized for signals running at a much higher rate (up to 14 Gbps).

Thanks and Regards,

Lee

0 RogerZ over 8 years ago in reply to Lee Sledjeski

Intellectual 295 points

Hi Sledjeski:

we have used this device on 1Gbps signal on our project , But there is a empty channel on the device not be used, So we used this empty channel as a ethernet switch;

0 Lee Sledjeski over 8 years ago in reply to RogerZ

TI__Mastermind 43795 points

Hi Roger,

I would reduce the peaking to minimum. There is no need for high frequency gain in this application.

EQ(x)0 = 0

EQ(x)1 = 0

Se if this improves the output waveform. There seems to be some interaction with the transformer - hopefully reduced peaking will improve this situation.

Regards,

Lee

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SN65LVCP114: USE SN65LVCP114 to transport 100Mbps Ethernet signal met rise time and fall time issues.