Atec Agilent-346a - Manual (Page 12)

12
General-Purpose Probing
For All Agilent Logic Analyzers with 40-pin Pod Connectors
E5383A 17-Channel Single-Ended
Flying Lead Probe
Ideal when only a few lines may
need to be probed or probe points
are distributed across a target.
The E5383A includes a set of 20
IC test clips and five ground leads.
Logic Analysis
General-Purpose Probes
General-purpose probing requires
connecting probe leads to
individual signal lines. This
method is most convenient for
a small to moderate number of
signals, very flexible, and can be
used in conjunction with other
probing methods.
Note: Any probed signal line
must be able to supply a minimum
of 600 mV to the probe with the
specified loading.
The Standard Probing System
The standard probing system
consists of IC clips, probe leads,
probe housing and probe cable.
Because it is passive, the stan-
dard probing system is smaller,
lighter, and much easier to use
than active probing systems. This
passive probing system is similar
to a probing system used on a
high frequency oscilloscope. It
consists of an isolation network
(as shown in Figure 4.1) at the
probe tip and a shielded resistive
transmission line. The advantages
of this system are:
• High input impedance. See
Figure 4.1.
• Signal ground at the probe tip
for high-speed signals.
• Inexpensive, removable probe
tip assemblies.
Probe Leads and Lead Sets
Probe leads are configured into
lead sets, which can probe 16
data channels with ground, one
clock channel, and a common
ground. A 17-channel probe
lead set (E5383A) is shown in
Figure 4.2, along with the replace-
ment part numbers for individual
components in Figure 4.3.
Each probe lead is a 12-inch,
twisted-pair cable connected to
the probe cable at the probe hous-
ing (see Figure 4.3). The probe tip
includes a signal lead, a connec-
tor for a ground lead, and the
isolation network.
The signal and ground leads
can be connected directly to the
target system. This requires
installing 0.63 mm (0.025 in)
square pins, or round pins with
a diameter of between 0.66 mm
(0.026 in) and 0.84 mm (0.033 in)
directly on the board. An IC test
clip can also be used. The same
specifications apply for the pin
dimensions of the test clip.
(See Figure 4.6 for IC test clips
available from Agilent.)
Figure 4.1. Probe tip Isolation network and equivalent load
Equivalent Load Tip Isolation Network
Figure 4.3. E5383A 17-channel probe lead set replacement parts
Common ground
lead (long)
(Agilent part number
5959-9335 contains
5 pod grounds)
Probe housing
Probe lead
(Agilent part number 5959-9333
contains 5 probe leads)
Each probe lead set contains:
1 clock probe lead
16 data line leads
RC network housing
Connector for
ground lead
Signal leads
Ground leads
(Agilent part number
5959-9334 contains
5 short ground leads)
Figure 4.2. E5383A 17-channel probe
lead set
SMD IC clip
(Agilent part number
5090-4833 contains 20 clips)