DS100MB201: output wave abnormal

user3587759

Part Number: DS100MB201

Dear all:

I connet 1Gbps input signal and I confige RATE=0,TXIDLEDO/SO =float or 0，SD_TH= float , FAN OUT =0, and I capture the wave at input and output, find waves are abnormal , if there are continus high or low at input , the outputs are abnormal , and output waves have only a pluse wave at the edge of input , attach the wave ,green is the input and yellow is the output

over 6 years ago

0 Lee Sledjeski over 6 years ago

TI__Mastermind 43795 points

Hi,
Did you AC couple the input signals from the generator or transmiter?

Regards,
Lee

0 user3587759 over 6 years ago in reply to Lee Sledjeski

Prodigy 40 points

Hi ,

Yes，I have tried 0.1uf / 0.01uf ，waves are looked same before and after the couple capacities ， and both generator and transmitter are CML logic

0 Lee Sledjeski over 6 years ago in reply to user3587759

TI__Mastermind 43795 points

Hi,

It could be in the pin configuration. Could you attach a schematic.

Thanks and Regards,

Lee

0 Andonis Wang over 6 years ago in reply to Lee Sledjeski

TI__Prodigy 280 points

Hi Lee,

Thanks for your help here. The post is actually from one of my customers and we worked out the issue offline. The reason is they do not set the corresponding registers (0x18, 0x26, 0x2E, 0x35, 0x3C, 0x43) to 0x01 as required in the datasheet before the operation. After setting those registers, the issue is gone.

One question left is is there a way to avoid programming the chip and use it with default settings? If not, then what is the function of programming those registers to 0x01? (From datasheet, it says these registers are used to set up the output voltage, but can you elaborate it a little bit? I assume the output voltage can simply follow the input without extra help).

B.R.

Andonis

0 Lee Sledjeski over 6 years ago in reply to Andonis Wang

TI__Mastermind 43795 points

Hi Andonis,

The output design on this design did not work as expected by default. The alternate programming is necessary to achieve appropriate output levels.

Regards,

Lee

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DS100MB201: output wave abnormal