User`s guide

2 Installation
40 Model N6705 User’s Guide
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Parallel Connections
CAUTION
Only connect outputs that have identical voltage and current ratings in parallel.
Agilent Models N678xA SMU cannot be connected in parallel.
Connecting outputs in parallel provides a greater current capability
than can be obtained from a single output.
The following figures show how to connect two outputs in parallel.
The figure on the left illustrates local sensing. If voltage drop in the
load leads is a concern, the figure on the right shows how to connect
the sense leads directly at the load (4-wire sensing).
Once outputs have been connected in parallel, they can be configured
or “grouped” to act as a single, higher-power output. This applies
when programming via the front panel or using SCPI commands.
How to group outputs that have been connected in parallel is
discussed in Chapter 6 under “Output Grouping”.
1. Twist leads
2. 4-wire
disabled
(indicator
is off)
3. 4-wire
enabled
(indicator
is on)
Effect on Specifications
Specifications for outputs operating in parallel can be obtained from
the specifications for single outputs. Most specifications are
expressed as a constant or as a percentage (or ppm) plus a constant.
For parallel operation, the percentage portion remains unchanged
while constant portions or any constants are changed as indicated
below. For current readback accuracy and temperature coefficient of
current readback, use the minus current specifications:
Current
All parallel specifications referring to current are twice the single output
specification except for programming resolution, which is the same for both
single output and parallel output operation.
Voltage
All parallel specifications referring to voltage are the same as for a single
output except for CV load effect, CV load cross regulation, CV source effect,
and CV short term drift. These are all twice the voltage pr
ogramming accuracy
(including the percentage portion) at all operating points.
Load Transient
Recovery Time
Load transient specifications are typically twice the single output.