Hi everybody,
I am designing LNA and run into the issue of bonding wire S- parameter. The test bench for input LNA is described as below capture.
My bonding wire inductor is about L=0.44 nH/ Q= 25 @ 2.5 GHz, to test whether performance is improved if using multiple bonding wires, I connect 10 wires (just for simulation, not realistic bonding case) in parallel (as seen in the captured)
I hope that its equivalent L_bonding will be L/10 and in fact, with the simulation result ( use differential testbench 2 ports to measure equivalent L bonding) my prediction is correct (figure 1) - about 44p with Q almost similar
However, it is quite troublesome when I do simulation with that S-parameter file, the Gain is dropped to 0 as well as input matching disappears, but the Gain gets normally recovered (Figure 2) once I replace that L bonding S-param file by an inductor having the same specs( Q=25, L = 44p @ 2.5 G). It is quite weird and subtle to me even the passivity of the bonding wire S-param file was carefully checked.
My question: Is that correct if I equivalate those 10 bonding wires by arraying 10 files S-parameters 2 ports in parallel? and How can i deal with it ?
Very much appreciated receiving your help!
Thanks
Binh Ngo
(capture 1)
figure 1
Figure 2