5968-4632E Datasheet, PDF (66/77 Pages) Keysight Technologies – Probing Solutions for Logic Analyzers

66 | Keysight | Probing Solutions for Logic Analyzers - Data Sheet
Probing Solutions for 40-pin Logic Analyzers
Mictor and Samtec Probing (Continued)
Keysight E5351A 38-pin adapter cable
If the calculated electrical length of the required routing stub prohibits the use of the
Keysight E5339A, E5346A, or E5385A, the Keysight E5351A can be used with the
required isolation networks installed on the target.
The E5351A does not have its own internal isolation networks. When using the E5351A,
place the SIP isolation networks or equivalent discrete components very near the
target component for measurement. Ensure that the stub length between the target
component and the isolation network is short. The stub propagation delay should be
less than 20% of the bus signal rise time, as mentioned before. The transmission line
from the on-board isolation network to the Mictor connector should be designed for an
impedance in the range of 80 to 100 ohms (closer to 100 ohms is better). This length
should not exceed 3 to 4 inches, and all signal line lengths should be equal. Signal line
length variation should not cause propagation delay variation to exceed 20 ps between
signal lines.
Notes on using discrete components
Discrete components can be used in the design of the RC network. Keysight
recommends the circuit shown in Figure 9.31. To achieve the equivalent load shown in
the figure, trace lengths should be minimized by locating the RC network very near the
measured node. Actual load will be the stub length load added to the equivalent load in
the figure.
pF
k
Figure 9.30. Keysight E5351A design rules.
E5351A Probe