ACPL-P341-000E Avago Technologies US Inc., ACPL-P341-000E Datasheet - Page 17

• Manufacturer Part Number: ACPL-P341-000E
• Description: Gate Drive Optocoupler,LF
• Manufacturer: Avago Technologies US Inc.

Specifications of ACPL-P341-000E

• No. Of Channels: 1
• Optocoupler Output Type: Gate Drive
• Input Current: 16mA
• Opto Case Style: SOIC
• No. Of Pins: 6
• Leaded Process Compatible: Yes
• Peak Reflow Compatible (260 C): Yes
• Rohs Compliant: Yes
• Lead Free Status / Rohs Status: Details

LED Drive Circuit Considerations for High CMR Performance
Figure 26 shows the recommended drive circuit for the
ACPL-P341/W341 that gives optimum common-mode
rejection. The two current setting resistors balance the
common mode impedances at the LED’s anode and
cathode. Common-mode transients can be capacitive
coupled from the LED anode, through C
through C
to be shunted away from the LED (which is not wanted
when the LED should be on) or conversely cause current
to be injected into the LED (which is not wanted when the
LED should be off ).
Table 8 shows the directions of I
polarity of the common-mode transient. For transients
occurring when the LED is on, common-mode rejection
(CM
LED current (I
switching threshold (I
extent to which I
words, any condition where a common-mode transient
causes a momentary decrease in I
and |I
mode failure for transients which are fast enough.
Likewise for a common-mode transient that occurs when
the LED is off (i.e. CM
Table 8. Common Mode Pulse Polarity and LED current Transients
17
dV
Positive (>0)
Negative(<0)
CM
H
/dt
, since the output is at “high” state) depends on
LP
| > |I
LC
LN
) to the output-side ground causing current
|, referring to Table 8) will cause a common-
F
). For conditions where I
LP
I
Away from LED anode
through C
Toward LED anode
through C
LP
and I
Direction
L
, since the output is at “low” state),
FLH
LN
), CM
LA
LA
balance each other. In other
LP
H
F
and I
also depends on the
(i.e. when dV
LN
F
LA
depend on the
is close to the
(or cathode
I
Away from LED cathode
through C
Toward LED cathode
through C
LP
CM
Direction
/dt > 0
LC
LC
if an imbalance between I
I
optocoupler, the transient “signal” may cause the output
to spike above 1 V, which constitutes a CM
balanced I
mode voltage change at the anode and cathode. The
shunt drive input circuit will also help to achieve high CM
performance by shunting the LED in the off state.
+5 V
Figure 26. Recommended high-CMR drive circuit for the ACPL-P341/W341
F
equal to or greater than the switching threshold of the
LED
R
R
1
CATHODE
-setting resistors help equalize the common
2
If |I
I
Increase
Decrease
ANODE
F
is momentarily
LP
1
2
3
| < |I
LN
|,
I
C
I
C
LP
LP
LN
LA
LC
V
R
R
R
DD
1
2
1
/R
and I
= 205
= 137
= 5.0 V:
2
≈ 1.5
LN
±1%
±1%
If |I
I
Decrease
Increase
F
results in a transient
is momentarily
LP
| > |I
LN
L
failure. The
|,
6
5
4
V
V
V
CC
OUT
EE
L