poyu
Newbie level 4
common mode return loss
I am studying the LVDS driver. However, I don't know how to check the common mode return loss performance by hspice. I tried to use ac analysis to find ZIN first. Then, using the formula for reflection coefficient to get the return loss.
Γ=(Z2-Z1/Z2+Z1) Z2: 45ohm cable impedance Z1: ZIN from ac analysis
Finally, transferring the value of reflection coefficient to dB for common mode return loss.
I am not sure the answer is right or not.
My spice code to get ZIN:
vref vref 0 0.75 *0.5VDD
vac TDP TDN ac=1
xpkg1 TDP RP *RLC for package bonding wire load
xpkg2 TDN RN *RLC for package bonding wire load
RT1 RDP 0 45 *45ohm termination in RX
RT2 RDN 0 45 *45ohm termination in RX
.net vac
.ac dec 20 10 10G
.probe ac zin
I am studying the LVDS driver. However, I don't know how to check the common mode return loss performance by hspice. I tried to use ac analysis to find ZIN first. Then, using the formula for reflection coefficient to get the return loss.
Γ=(Z2-Z1/Z2+Z1) Z2: 45ohm cable impedance Z1: ZIN from ac analysis
Finally, transferring the value of reflection coefficient to dB for common mode return loss.
I am not sure the answer is right or not.
My spice code to get ZIN:
vref vref 0 0.75 *0.5VDD
vac TDP TDN ac=1
xpkg1 TDP RP *RLC for package bonding wire load
xpkg2 TDN RN *RLC for package bonding wire load
RT1 RDP 0 45 *45ohm termination in RX
RT2 RDN 0 45 *45ohm termination in RX
.net vac
.ac dec 20 10 10G
.probe ac zin