Active output impedance for ADSL line drivers

Hello Arun,

I am not sure I understand your question.  Can you give the part number that you are referring to?  Is there a datasheet parameter you are asking about, or is this an application circuit question?

Regards,

Loren

Hello All,

I found this information about active termination (Fully-Differential Amplifiers, section 16) which may be helpful?

Regards,

Hooman

Hello Arun,

There are several ways to terminate a transmission line or transformer circuit.  The most broadband method is to use a low parasitic resistor.  This gives very good termination but adds noise.  Inductors and capacitors can be used for termination, they are essentially noiseless but provide a match at only at one specific frequency.

A compromise is to use the loop gain of an amplifier to provide a broadband termination.  This solution requires a wide bandwidth amplifier and adds some noise, but less than a resistor. 

The articles you reference are specific to DSL, but the principal can be used in other circuits. 

If you look in the datasheets for our LMH3401 or LMH5401 broadband fully differential amplifiers you will see that active termination can be used for input termination as well as output termination. 

Regards,

Loren

Hi Loren,

Thanks for your reply,

Now i got little bit idea about Active termination, I will go through those documents,

Thanks for your time.

-Arun