ACPL-W314-500E Avago Technologies US Inc., ACPL-W314-500E Datasheet - Page 12

• Manufacturer Part Number: ACPL-W314-500E
• Description: OPTOCOUPLER IGBT 0.4A 6-SOIC
• Manufacturer: Avago Technologies US Inc.

Specifications of ACPL-W314-500E

• Output Type: Push-Pull, Totem-Pole
• Package / Case: 6-SOP
• Voltage - Isolation: 3750Vrms
• Number Of Channels: 1, Unidirectional
• Current - Output / Channel: 600mA
• Propagation Delay High - Low @ If: 300ns @ 7mA
• Current - Dc Forward (if): 25mA
• Input Type: DC
• Mounting Type: Surface Mount
• Fall Time: 50 ns
• Rise Time: 50 ns
• Configuration: 1 Channel
• Isolation Voltage: 3750 Vrms
• Maximum Propagation Delay Time: 700 ns
• Maximum Forward Diode Voltage: 1.8 V
• Minimum Forward Diode Voltage: 1.2 V
• Maximum Reverse Diode Voltage: 5 V
• Maximum Forward Diode Current: 12 mA
• Maximum Power Dissipation: 250 mW
• Maximum Operating Temperature: + 100 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

LED Drive Circuit Considerations for Ultra High CMR Per-
formance
Without a detector shield, the dominant cause of opto-
coupler CMR failure is capacitive coupling from the input
side of the optocoupler, through the package, to the
detector IC as shown in Figure 21. The ACPL-P314/W314
improves CMR performance by using a detector IC with
an optically transparent Faraday shield, which diverts the
capacitively coupled current away from the sensitive IC
circuitry. However, this shield does not eliminate the ca-
pacitive coupling between the LED and optocoupler pins
5-8 as shown in Figure 22. This capacitive coupling causes
perturbations in the LED current during common mode
transients and becomes the major source of CMR failures
for a shielded optocoupler. The main design objective of
a high CMR LED drive circuit becomes keeping the LED in
the proper state (on or off ) during common mode tran-
sients. For example, the recommended application circuit
(Figure 19), can achieve 10 kV/Ps CMR while minimizing
component complexity.
Techniques to keep the LED in the proper state are
discussed in the next two sections.
Figure 21. Optocoupler Input to Output Capacitance Model for Unshielded
Optocouplers.
Figure 22. Optocoupler Input to Output Capacitance Model for Shielded
Optocouplers.
CMR with the LED On (CMR
A high CMR LED drive circuit must keep the LED on
during common mode transients. This is achieved by
overdriving the LED current beyond the input threshold
so that it is not pulled below the threshold during a
transient. A minimum LED current of 8 mA provides
adequate margin over the maximum I
achieve 10 kV/μs CMR.
12
1
1
2
2
3
3
1
1
2
2
3
3
C
C
C
C
C
C
C
C
LEDP
LEDP
LEDN
LEDN
LEDP
LEDP
LEDN
LEDN
C
C
LED01
LED01
SHIELD
SHIELD
C
C
LED02
LED02
H
)
6
6
5
5
4
4
6
6
5
5
4
4
FLH
of 5 mA to
CMR with the LED Off (CMRL)
A high CMR LED drive circuit must keep the LED off (V
d V
during a -dV
flowing through C
V
developed across the logic gate is less than V
LED will remain off and no common mode failure will
occur.
+ 5 V
Figure 23. Equivalent Circuit for Figure 17 During Common Mode Transient.
The open collector drive circuit, shown in Figure 24, can
not keep the LED off during a +dV
all the current flowing through CLEDN must be supplied
by the LED, and it is not recommended for applications
requiring ultra high CMR1 performance. The alternative
drive circuit which like the recommended application
circuit (Figure 19), does achieve ultra high CMR perfor-
mance by shunting the LED in the off state.
Figure 24. Not Recommended Open Collector Drive Circuit.
SAT
+5 V
+5 V
F(OFF)
Q1
Q1
Q1
of the logic gate. As long as the low state voltage
) during common mode transients. For example,
+
+
+
V
V
V
-
-
-
SAT
SAT
SAT
1
1
2
2
3
3
CM
I
I
LEDN
LEDN
C
C
1
2
3
/dt transient in Figure 23, the current
LEDP
LEDP
THE ARROWS INDICATE THE DIRECTION
C
C
OF CURRENT FLOW DURING - dV
LEDN
LEDN
LEDP
C
C
LEDN
LEDP
I
I
LEDP
SHIELD
SHIELD
also flows through the R
SHIELD
V
CM
CM
CM
/ dt
/dt transient, since
6
6
5
5
4
4
0.1 F
6
5
4
F(OFF)
+
+
-
-
SAT
V
CC
= 18V
R
and
g
the
F