Hi All,
Is 100 ohms typical output impedance of a PCIe differential driver ?
I plotted I,V curve in excel and got R=50 ohms. I guess this is only for
NON-INV pin and so differential impedance should still be 100 ohms.
I also see in ADS a Differential voltage Swing of +/-400mV at IBIS_Tx**
(measured at Tx) when No Load (open end) is connected.
and +/-200mV output (measured at Tx again) when I connect a low loss* Load
(a S parameter Model of PCB Differential trace followed by a PCIe Rx IBIS
model).
So, theoretical maximum voltage that I see at the receiver is always half
of what transmitter is outputting?
So Ideally (very low loss) for Full swing of 1200mV/800mV at Tx, I'll only
see 600mV/400mV at the Load ?
and similarly for Half Swing of 700mV/400mV, I'll see 350mV/200mV at the
load ?
**(Vhigh and Vlow set to +400 & -400mV).
*100 ohm, half inch, Differential traces with 0.2-0.3dB loss at 2.5GHz
Thank you,
Praveen
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