IRF7738L2PBF Datasheet, PDF (6/10 Pages) International Rectifier – DirectFET

Power MOSFET

160
TOP
Single Pulse
140
BOTTOM 1.0% Duty Cycle
ID = 109A
120
100
80
60
40
20
0
25 50 75 100 125 150 175
Starting TJ , Junction Temperature (°C)
Fig 17. Maximum Avalanche Energy Vs. Temperature
15V
VDS
L
DRIVER
RG
2^V0V^GS
tp
D.U.T
I_AS
0.01Ω
+
- ^VDD
A
Fig 18a. Unclamped Inductive Test Circuit
L
VCC
DUT
0
210K
S
IRF7738L2PbF
Notes on Repetitive Avalanche Curves , Figures 16, 17:
(For further info, see AN-1005 at www.irf.com)
1. Avalanche failures assumption:
Purely a thermal phenomenon and failure occurs at a
temperature far in excess of T_jmax. This is validated for
every part type.
2. Safe operation in Avalanche is allowed as long asT_jmax is
not exceeded.
3. Equation below based on circuit and waveforms shown in
Figures 18a, 18b.
4. P_{D (ave)} = Average power dissipation per single
avalanche pulse.
5. BV = Rated breakdown voltage (1.3 factor accounts for
voltage increase during avalanche).
6. I_av = Allowable avalanche current.
7. ∆T = Allowable rise in junction temperature, not to exceed
T_jmax (assumed as 25°C in Figure 16, 17).
t_{av =} Average time in avalanche.
D = Duty cycle in avalanche = t_av ·f
Z_thJC(D, t_av) = Transient thermal resistance, see figure 15)
P_{D (ave)} = 1/2 ( 1.3·BV·I_av) = DT/ Z_thJC
I_av = 2DT/ [1.3·BV·Z_th]
E_{AS (AR)} = P_{D (ave)}·t_av
V(BR)DSS
tp
I _AS
Fig 18b. Unclamped Inductive Waveforms
Id
Vds
Vgs
Vgs(th)
Fig 19a. Gate Charge Test Circuit
V_DS
V_GS
R_G
R_D
D.U.T.
+
- _VDD
Qgodr
Qgd Qgs2 Qgs1
Fig 19b. Gate Charge Waveform
V_DS
90%
10V
Pulse Width ≤ 1 µs
Duty Factor ≤ 0.1 %
Fig 20a. Switching Time Test Circuit
10%
V_GS
t_d(on) t_r
t_d(off) t_f
Fig 20b. Switching Time Waveforms
6
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February 13, 2014