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www.fairchildsemi.com
FODM3051, FODM3052, FODM3053 Rev. 1.0.0
FODM3051, FODM3052, FODM3053 4-Pin Full Pitch Mini-Flat Package Random Phase Triac Driver Output Optocouplers
Figure 8. Static dv/dt Test Circuit
Vdc
400V
R = 10 kΩ
C
TEST
X100
SCOPE
PROBE
PULSE
INPUT
MERCURY
WETTED
RELAY
252 V
0 VOLTS
APPLIED VOLTAGE
WAVEFORM
V
max
=
dv/dt =
0.63 V
max
=
252
R
TEST
D.U.T.D.U.T.
τ
RC
τ
RC
τ
RC
400 V
Fig. 7 On-State Characteristics
V
TM
- ON-STATE VOLTAGE (V)
T
A
= 25°C
I
TM
- ON-STATE CURRENT (mA)
-800
-6 -4 -2 0 2 4 6
-600
-400
-200
0
200
400
600
800
1. The mercury wetted relay provides a high speed
repeated pulse to the D.U.T.
2. 100x scope probes are used, to allow high speeds
and voltages.
3. The worst-case condition for static dv/dt is estab-
lished by triggering the D.U.T. with a normal LED
input current, then removing the current. The vari-
able R
TEST
allows the dv/dt to be gradually
increased until the D.U.T. continues to trigger in
response to the applied voltage pulse, even after
the LED current has been removed. The dv/dt is
then decreased until the D.U.T. stops triggering.
τ
RC
is measured at this point and recorded.
