Designing an Interface Between a P6434 Probe and a SUT
P6434 Probe Instructions 17
The Low-Profile Extender used with the P6434 probe increases the load. The
additional load is equivalent to a 100 W resistor connected in series with
approximately three inches of 75 W coaxial cable to the probe tip.
Although the extender can increase the loading significantly, using the extender
might be necessary in situations where there is as little as half an inch of
clearance.
The extender is useful in a SUT where signal risetimes are greater than one or
two nanoseconds. Faster risetimes cause transmission line reflections on signals.
Figure 13 shows the equivalent circuit for the P6434 probe with a Low-Profile
Extender.
1.6 nH
1.6 nH
0.7 pF
0.005 W
0.005 W
100 W
Length = 3 inches
0.005 W
1.6 nH 0.7pF
0.005 W
1.1 pF 20 kW
0.23 pF
Length = 58 inches
LOSSY
+2.2 V
LOSSY
1.6 nH
75 W
Mictor connector equivalent circuit Mictor connector equivalent circuit
Figure 13: Equivalent circuit for the P6434 probe with a Low-Profile Extender