Configuration Settings - Keithley 6220 Reference Manual

Model 6220/6221 Reference Manual
Duty cycle
Duty cycle defines the ratio between pulse "on" time and pulse "off" time during a
Pulse Delta cycle. For example, for a 25% duty cycle, the pulse would be "on"
(high) for one-quarter of the cycle, and "off" (0mA low) for three-quarters of the
cycle. Pulse Delta cycles with a short duty-cycle can be sourced to prevent heat
from adversely affecting the measurement of low power DUT.
When using a 0mA low level (which is the default), the duty cycle for the Pulse
Delta cycle is calculated as follows:
DutyCycle
Where:
Pulse Delta cycle time period
Sweep output – The time period for each Pulse Delta cycle is the same as the
sweep delay time that is set by the user when configuring the sweep.
Fixed output – The Pulse Delta cycle (interval) is expressed as the number of
power line cycles (PLC). This PLC value must be converted into time (seconds) as
follows:
For 60Hz line power:
Pulse Delta cycle time period = Interval setting (PLC) x 16.667ms
For 50Hz line power:
Pulse Delta cycle time period = Interval setting (PLC) x 20ms
Example – For 60Hz line power, the Pulse Delta cycle time period for an Interval
setting of 5 PLC is calculated as follows:
Pulse Delta cycle time period = 5 x 16.667ms

Configuration settings

Pulse Delta settings from the front panel are described as follows. These parame-
ters are set from the CONFIG PULSE DELTA menu that is accessed by pressing
the CONFIG key and then the PULSE key.
The equivalent remote programming commands to configure Pulse Delta are
summarized in
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Delta, Pulse Delta, and Differential Conductance 5-39
PulseWidth
------------------------------------------------ - 100
=
PulseDeltaCycle
DutyCycle = Duty cycle expressed as a percent.
PulseWidth = User specified Pulse Width (in seconds).
PulseDeltaCycle = Time period (in seconds) for each Pulse Delta cycle
(see "Pulse Delta cycle time period").
= 83.33ms
Table 5-4.
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