Keithley 2635 Reference Manual

2600S-901-01 Rev. C / January 2008 Return to Section Topics 8-5
Series 2600 System SourceMeter® Instruments Reference Manual Section 8: Source-Measure Concepts
• High power pulse operation is not being used.
However, if any one of these is false, the SourceMeter may overheat if operated in a manner that
exceeds the calculated maximum duty cycle, DC
MAX
.
The maximum duty cycle equation is derived from the power equation below by solving for DC
MAX
.
The general power equation describes how much power a SourceMeter channel can source and/
or sink before the total power cannot be fully dissipated by the SourceMeter cooling system. This
equation takes into account all of the factors that can influence the power being dissipated by the
SourceMeter.
General SourceMeter power equation
V
OA
V
P
–()I
P
()DC
MAX
V
OA
V
B
–()I
B
() P
CS
T
DER
–()≤+
P
CS
= The maximum power generated in a SourceMeter channel that can be properly dissipated
by the SourceMeter cooling system.
T
AMB
= The ambient temperature of the SourceMeter operating environment.
T
DER
= T
AMB
- 30
• This factor represents the number of watts the SourceMeter is de-rated when oper-
ating in environments above 30°C. This is represented as a temperature because
the maximum output power of each SourceMeter channel is reduced by 1W per
degree C above 30°C.
•T
DER
is 0 when the ambient temperature is below 30°C.
V
OA
= The SourceMeter output amplifier voltage. This constant can be found in the tables below.
V
P
= The voltage level the SourceMeter is attempting to force while at the pulse level.
• When operating in quadrants 1 or 3 (sourcing power), the sign of this voltage must
be positive when used in the power equations.
• When operating in quadrants 2 or 4 (sinking power), the sign of this voltage must be
negative when used in the power equations.
V
B
= The voltage level the SourceMeter is attempting to force while at the bias level.
• When operating in quadrants 1 or 3 (sourcing power), the sign of this voltage must
be positive when used in the power equations.
• When operating in quadrants 2 or 4 (sinking power), the sign of this voltage must be
negative when used in the power equations.
I
P
= The current flowing through the SourceMeter channel while at the pulse level.
I
B
= The current flowing through the SourceMeter channel while at the bias level.

Keithley 2635 Specifications

General

Brand	Keithley
Model	2635
Category	Measuring Instruments
Language	English