61 | Keysight | Probing Solutions for Logic Analyzers - Data Sheet
Probing Solutions for 40-pin Logic Analyzers
Soft Touch Connectorless Probing (Continued)
Equivalent probe loads
The following probe load models are based on in-circuit measurements made with a
Keysight 8753E 6 GHz network analyzer and a Keysight 54750A TDR/TDT using a 50 Ω
test fixture. The following schematic accurately models the probe load out to 6 GHz.
Din
Rtap
400
Cstub
0.375 pF
Ctip
10 pF
Rtip
100 K
Figure 9.20. Simple (does not include capacitive coupling between channels or inductance of the
spring pins).
Din
Lspring1
0.63 nH
Lspring2
1.17 nH
Rtip1
250
Ccoupling
0.070 pF
Cstub
0.375 pF
Ct
10
Rgnd1
10
Rtip2
100 K
Rg
12
Figure 9.21. Complex (includes capacitive coupling between channels and inductance of spring
pins).