haribabu
Junior Member level 2
lvds transmitter cmfb
HI ,
I had a problem in modeling the LVDS transmitter for stability analysis. I am using the standard LVDS transmitter with CMFB circuit. The attachment contains the model of the LVDS circuit. I put my problem in the following points.
1.While determining the pole at the output of the transmitter I am assuming that I have to take receiver load capacitance in to account and this load capacitance
depends on number of receivers connected to it .If it is the case , then from the LVDS standard it is said that a maximum 32 receivers can be connected .So the pole varies from 1X to 32X (Where X is the pole frequency when there is only one receiver). In such a case it is difficult to stabilize the circuit .How do we handle this
problem ?
2.Can I neglect the loading effect of terminating resistor (100 ohm between the two transmission lines at the receiver side ) as it seeing same common mode voltage at its both ends i.e the resistance is effectively ZERO .
3.Is it the right thing to take the 50 ohm resistor (Tx line impedance ) in to account and say that my R for the output pole will be approximately 25 ohm (the two 50 ohm resistors come in Parallel to give 25 ohm assuming that the effect of terminating resistor is not there bcoz of above statement )
4..Please suggest any paper that talks about modeling of the LVDS transmitter in order to analyze its stability
HI ,
I had a problem in modeling the LVDS transmitter for stability analysis. I am using the standard LVDS transmitter with CMFB circuit. The attachment contains the model of the LVDS circuit. I put my problem in the following points.
1.While determining the pole at the output of the transmitter I am assuming that I have to take receiver load capacitance in to account and this load capacitance
depends on number of receivers connected to it .If it is the case , then from the LVDS standard it is said that a maximum 32 receivers can be connected .So the pole varies from 1X to 32X (Where X is the pole frequency when there is only one receiver). In such a case it is difficult to stabilize the circuit .How do we handle this
problem ?
2.Can I neglect the loading effect of terminating resistor (100 ohm between the two transmission lines at the receiver side ) as it seeing same common mode voltage at its both ends i.e the resistance is effectively ZERO .
3.Is it the right thing to take the 50 ohm resistor (Tx line impedance ) in to account and say that my R for the output pole will be approximately 25 ohm (the two 50 ohm resistors come in Parallel to give 25 ohm assuming that the effect of terminating resistor is not there bcoz of above statement )
4..Please suggest any paper that talks about modeling of the LVDS transmitter in order to analyze its stability
