Filter
Top Products
Designing an Interface Between a P6434 Probe and a SUT
16
P6434 Probe Instructions
Pin 1 Indicator
Be sure to place a pin 1 indicator on your circuit board during design. If you
include the latch housing in your design, it will obscure the pin 1 indicator on the
Mictor connector. Although the Mictor connector is keyed, you still need to
know the location of pin 1 when connecting the P6434 probe.
Loading and Equivalent Circuits
The load presented to the SUT by the P6434 probe is low. The load is equivalent
to a 2 pF capacitance with 20 kW resistance returned to a 2.2 V supply. The
following approximation of the probe loading is sufficient for most circuit
simulation calculations.
Figure 12 shows the equivalent circuit of the P6434 probe. Table 5 shows the
values you can use to calculate characteristics of the lossy delay lines shown in
the next two figures.
Table 5: Lossy delay line values
Characteristic Value
C (capacitance) 1.58 pF per inch
L (inductance) 8.9 nH per inch
R (resistance)
0.067 W per inch
Z
0
(impedance)
75 W
0.005
1.6 nH
0.7 pF
0.005
20 kW
0.23 pF
Length = 58 inches
LOSSY
+2.2 V
1.6 nH
1.1 pF
W
W
75
W
Mictor connector
equivalent circuit
Figure 12: Equivalent circuit for the P6434 probe