5968-4632E Datasheet, PDF (61/77 Pages) Keysight Technologies – Probing Solutions for Logic Analyzers

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
Cstub
0.375 pF
400
Din
Rtip
100 K
Cstub
0.375 pF
Rtap
Ctip
1⁴⁰0⁰pF
Rtip
100 K
Ctip
10 pF
Figure 9.20. Simple (does not include capacitive coupling between channels or inductance of the
spring pins).
Din
Lspring1
Lspring2
Rtip1
Lspring2
Ccoupling
0.070 pF
0.63 nHRtip1
Cstub
0.375 pF
1.17 nH
250
1.17 nH
R²g⁵nd⁰1
10
pF
Rtip2
Ctip ^{100 K}
10 pF
Ctip
10 pF
Rgnd2
120
Figure 9.21. Complex (includes capacitiv^Re^tic^po²upling between channels^Ra^gnⁿd^din²ductance of spring
pins).
100 K
120