Tch ( ) = Ta + Pa •
+ (P1–Pa) •
r
r
ch-c (Tn +T+t1 + t2 + t3)
Tch ( 1) = Ta + Pa •
+ (P1–Pa) •
r
ch-c (Tn +T' +t1 + t2 + t3)
ch-c (T+t1 + t2 + t3)
rch-c (T' +t1 + t2 + t3)
– (P1 – P2) •
rch-c (T+t2 + t3)
– (P1 – P2) •
rch-c (T '+t2 + t3)
+ (P3 – P2) •
rch-c (T+t3)
+ (P3 – P2) • rch-c (T' +t3)
– P3 •
r
ch-c (T) +P4 •
r
ch-c (t4 + t5 + t6)
– P3 •
r
ch-c (T') +P4 •
r
ch-c (t4 + t5 + t6)
ch-c (t5 + t6)
......................................
– (P4 – P5) •
rch-c (t5 + t6)
ch-c (t6)
– (P4 – P5) •
r
r
......................................
+ (P6 – P5) •
r
+ (P6 – P5) •
ch-c (t6)
3
4
Ta
: Ambient temperature
*
This Tch ( 1) value becomes Tch (start). If the avalanche
energy (EAS = P 6•t6) is within the value derated from the
guaranteed EAS value at the temperature, there is no
problem as far as the avalanche energy is concerned.
rch-c (t): Transient thermal resistance at pulse width t
Then calculate the channel temperature Tch ( 1) imme-
diately before avalanche.
Transient Stationary
Fig. C
Fig. D
P6
P3
P1
P4
PP2
P5
Pa
VDS
0
ID
T(n)
t1 t2
t
t3
t4 t5 t6
T
T'
0
T(n)
1
Avalanche in this section
Avalanche energy capability measuring method
Fig. 1
V(BR) DSS
V(BR) DSS – VDD
1
2
2
EAS
=
• L • ILp
•
L
V(BR) DSS
IL
VDS
ILp
IL
RG
VDS
VDD
VGS
0V
VDD
(b) Output waveform
(a) Measuring circuit
Switching time measuring method
Fig. 2
Nch
(a) Measuring circuit
(b) Input-output waveform
RL
90%
VGS
ID
VDS
10%
90%
VDD
VGS
0V
RG
VDS
10%
td(on)
td(off)
tf
tr
=
P.W. 10µs
Duty cycle 1%
ton
toff
Fig. 3
Pch
RL
10%
VGS
ID
VDS
90%
10%
VDD
0V
RG
VDS
VGS
90%
td(on)
td(off)
tf
tr
=
P.W. 10µs
Duty cycle <1%
ton
toff
5
SANKEN [ SANKEN ELECTRIC ]
