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Insights from Spice. Adding Capacitance to Attenuation Resistors. Schematic with Resistor Capacitances. 1 meter of coax. Everything to the right of the 50 W resistor is on mezzanine. 5ns pulse with 1ns rise and fall. Effect of Resistor Capacitance. Without Capacitance.
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Insights fromSpice Adding Capacitance to Attenuation Resistors
Schematic with Resistor Capacitances 1 meter of coax Everything to the right of the 50 W resistor is on mezzanine. 5ns pulse with 1ns rise and fall
Schematic with Resistor Capacitance Same sweep of capacitance 1pF to 15pF
Capacitance Growth with Cell Count • Look at Ceff for: • 1 x 1 cell (single) • 3 x 3 cells where lines couple to other cells • 5 x 5 cells to examine growth with n2 cells • Clearly the absolute value of Ceffdepends on the line capacitance as well as the cell value.
One Cell Sub-circuit Cx = 38fF CapSnO2Line = 15fF CapNiLine = 22fF
Inject Charge Examine Voltage Current = 25mA for 200pS = 5000fC Voltage = 38.6V 130fF impied Note: All Capacitances outside the celll are 0 Note: All Inductors are 0
1 x 1 and 5x5 Results • For 1 x 1 cell the only capacitor is Cx = 38fF • After all the trouble to simulate, I got the obvious • For 3 x 3 cells the details are above • 5000fC yields 38.6V drop, Ceff = 130fF • For 5 x 5 cells the details are: • 5000fC yields 26V drop, Ceff = 192fF • Note: all these used Cline = 22fF & 15fF • Lines of different width & separation