Keysight Technologies N6705C, Руководство по эксплуатации и обслуживанию

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5. If the test fixture consists of pc traces, the positive and negative traces should be directly facing on
adjacent layers.
To minimize inductance, the width (w) of the traces should be at least as great as the thickness of the
dielectric (h). It is better to make the traces much wider than this minimum requirement in order to
minimize the DC resistance.
Low Bandwidth Mode with Remote or Local Sensing
All previously stated wiring requirements still apply in Low bandwidth mode except for the following.
The 15 cm maximum limit between the sense point and the load capacitor (see #4) does not apply
when using Low bandwidth mode.
Guard Connections
The purpose of a cable guard is to eliminate the effects of leakage current that can exist in the current
path of the external test circuit. The cable guard can be used when the test fixture requires guarding
and the power analyzer is sourcing or measuring DC currents under 1 μA. Without a guard, leakage
currents in the test circuit could affect the accuracy of the micro-amp measurements. Guarding is
generally not required when measuring currents 1 μA and greater.
You cannot connect to the front panel binding posts when using the Guard. You must
route ALL wires (guard, load, and sense) through the rear panel access ports of the
mainframe. Refer to the diagram under
High Current Output Connections for more
information. These access ports can also be used when extremely precise output
measurements are required.
As shown in the following figure, cable guards are available at the internal connector of Keysight
Models N678xA SMU. The guard is typically used to drive the shields of cables and test fixtures. It
provides a buffered voltage that is at the same potential as the + output terminals of the module
connector. The guard current is limited to about 300 μA.
Keysight N6705C Operating and Service Guide 59
2 Installation