AND9068/D
TJ * TC
and thermal, beyond which the functionality is no longer
IF +
guaranteed and at which physical damage may occur. The
absolute maximum rating does not guarantee that the device
will meet the data sheet specifications when it is within that
range. The specific voltage, temperature, current and other
limitations are called out in the Electrical Characteristics
table.
R
th(j−c)(diode) @ VF
The equation relating I and V to the temperature rise is
F
F
the same, although the R
for the diode is specified
th(j−c)
separately.
Diode Pulsed Current, IFM
The pulsed diode current describes the peak diode current
pulse above the rated collector current specification that can
flow while the junction remains below its maximum
temperature. The maximum allowable pulsed current in turn
depends on the pulse width, duty cycle and thermal
conditions of the device.
Collector−Emitter Voltage, VCES
The maximum rated voltage to be applied between the
collector and emitter terminals of the device is specified to
prevent the device from entering avalanche breakdown and
dissipating excessive energy in the device. The avalanche
breakdown voltage varies with temperature and is at its
minimum at low temperature. The breakdown voltage of the
device is designed to meet the minimum voltage rating at
−40°C.
Gate−Emitter Voltage, VGE
The gate−emitter voltage, V
describes maximum
GE
voltage to be applied from gate to emitter under fault
conditions. The gate−emitter voltage is limited by the gate
oxide material properties and thickness. The oxide is
typically capable of withstanding greater than 80V before
the oxide ruptures, but to ensure reliability over the lifetime
of the device, and to allow for transient overvoltage
conditions in the application, this voltage is limited to well
below the gate rupture voltage.
Collector Current, IC
The maximum collector current is defined as the amount
of current that is allowed to flow continuously into the
collector for a given case temperature, T , in order to reach
the maximum allowable junction temperature, T (150°C).
C
J
The collector current can be stated in the following equation
form:
TJ * TC
Power Dissipation, PD
The maximum power dissipation is determined using the
following equation:
IC
+
R
th(j−c)(IGBT) @ VCE(sat)
where R
CE(sat)
is the thermal resistance of the package and
is the on−state voltage at the specified current, I .
Since it is the current being sought after, and V
th(j−c)
TJ * TC
+
V
C
is a
PD
Rth(j−c)
CE(sat)
function of current, the equation must be solved iteratively.
An estimate of the V for a given collector current and
temperature can found in the typical datasheet curves,
discussed later.
It is very important to understand that the absolute
maximum collector current is defined based on very specific
electrical and thermal conditions. The capability of the
IGBT to conduct current without exceeding the absolute
maximum junction temperature is highly dependent on the
thermal performance of the system, including heatsinks and
airflow.
where R
is the thermal resistance of the package. The
th(j−c)
CE(sat)
maximum power dissipation is given at case temperatures of
25°C and 100°C, where the maximum junction temperature
is 150°C.
Short Circuit Withstand Time, tsc
The short circuit withstand time describes the ability of
the device to carry high current and sustain high voltage at
the same time. The device must withstand at least the rated
short circuit withstand time with specified voltages applied
from collector to emitter and from gate to emitter. The
collector−emitter voltage specified for the test will vary
based on the minimum blocking voltage capability of the
device. The gate−emitter voltage is usually 15 V. The current
flowing through the device under these conditions can far
exceed the rated current, and is limited by the IGBT forward
transconductance, an electrical parameter described below.
The failure mode during this fault condition is usually
thermal in nature.
Pulsed Collector Current, ICM
The pulsed collector current describes the peak collector
current pulse above the rated collector current specification
that can flow while remaining below the maximum junction
temperature. The maximum allowable pulsed current in turn
depends on the pulse width, duty cycle and thermal
conditions of the device.
Diode Forward Current, IF
The diode forward current is the maximum continuous
current that can flow at a fixed case temperature, T , while
remaining under the maximum junction temperature, T .
Operating Junction Temperature Range, TJ
This is the junction temperature range in which the device
is guaranteed to operate without physical or electrical
damage or reduced life expectancy.
C
J
This is determined in similar fashion to the V
, above.
CE(sat)
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