User`s guide

Installation 2
Model N6705 User’s Guide 35
Agilent N678xA SMU Wiring Requirements
NOTE
Because of the effect of wire inductance, the wire length information given in
the previous table does not apply to Agilent Models N678xA SMU.
To minimize the effect of wire inductance, the following table
describes the allowable load lead and wire length for several common
cable types. Using longer (or shorter) cable lengths than those
indicated in the table may cause output oscillation.
To N6705 front panel binding post
To N678xA module connector
Cable Type
Length in feet
Length in meters
Length in feet
Length in meters
Twisted pair (AWG 14 or smaller) 0 to 3.25 ft 0 to 1 m 1 to 4.25 ft 0.3 to 1.3 m
50 ohm coaxial (RG-58) 0 to 6.5 ft 0 to 2 m 2 to 10 ft 0.6 to 3 m
10 ohm coaxial (inductance per
cable foot ≤ 32 nH)
0 to 26 ft 0 to 8 m 8.5 to 33 ft 2 to 10 m
High Bandwidth Modes with Remote Sensing
The following wiring requirements apply when using Agilent Models
N678xA SMU in the High bandwidth modes with remote sensing.
Refer to chapter 6 under “Output Bandwidth” for more information
about the bandwidth settings.
1) Load wires must be twisted-pair or coax and must not be twisted
with the sense wires. Refer to the above table for length (L).
2) Sense wires must be twisted-pair or coax and must not be twisted
with the load wires.
3) No capacitors are allowed within the sense-compensated load
path.
4) If the load capacitor (C
L
) is not located at the sense point, the
distance from the sense point to the load capacitor cannot exceed
15 cm and must be twisted-pair, coax, or pc traces.
5) If the test fixture consists of pc traces, the positive and negative
traces should be directly facing on adjacent layers.
C L
4
5
1
2
3
L
< 15 cm
+ s
- s
+
-
N678xA