MRT100KP40A – MRT100KP400CA(e3)
tp – Pulse Time – sec. T
L
Lead Temperature °C
FIGURE 1 FIGURE 2
Peak Pulse Power vs. Pulse Time Power Derating
To 50% of Exponentially Decaying Pulse
NOTE: This P
PP
versus time graph allows the designer to use these
parts over a broad power spectrum using the guidelines illustrated in
MicroNote 104 on www.microsemi.com
. Aircraft transients are described
with exponential decaying waveforms. For suppression of square-wave
impulses, derate power and current to 66% of that for the exponential
decay shown in Figure 1.
CORRECT INSTALLATION INCORRECT
FIGURE 3 FIGURE 5
FIGURE 4 FIGURE 6
Peak Pulse Power (P
PP
) or
Continuous Power in % of 25°C rating
PP
Peak Pulse Power vs. Pulse Time – kW
Non-Repetitive Pulse
TVS devices used across power lines are
subject to relatively high magnitude surge
currents and are more
prone to adverse
parasitic inductance effects in the
mounting leads. Minimizing the shunt path
of the lead inductance and their V =
Ldi/dt effects will optimize the TVS
effectiveness. Examples of optimum
installation and poor installation are
il
lustrated in Figures 3 to 6. Figure 3
illustrates minimal parasitic inductance
with attachment at end of device.
Inductive voltage drop is across
the input
leads. Virtually no “overshoot” voltage
results as illustrated with Figure 4. The
loss of effectiven
ess in protection caused
by excessive parasitic inductance is
illustrated in Figures 5 and 6. Also see
MicroNote 111
for further information on
arasitic Lead Inductance in TVS”.
RF01012, Rev. C (15/06/15) ©2015 Microsemi Corporation Page 5 of 7
