ACPL-M46T-500E Avago Technologies US Inc., ACPL-M46T-500E Datasheet - Page 8

• Manufacturer Part Number: ACPL-M46T-500E
• Description: Amplifier-Output Optocoupler,1-CHANNEL,3.75kV ISOLATION,SO
• Manufacturer: Avago Technologies US Inc.
• Series: R²Coupler™r

Specifications of ACPL-M46T-500E

• Voltage - Isolation: 3750Vrms
• Number Of Channels: 1, Unidirectional
• Current - Output / Channel: 50µA
• Data Rate: 1MBd
• Propagation Delay High - Low @ If: 200ns @ 10mA
• Current - Dc Forward (if): 20mA
• Input Type: DC
• Output Type: Open Collector
• Mounting Type: Surface Mount
• Package / Case: SO-5 (MO-155)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

IPM Dead Time and Propagation Delay Specifications
The ACPL-M46T includes a Propagation Delay Difference
specification intended to help designers minimize “dead
time” in their power inverter designs. Dead time is the
time period during which both the high and low side
power transistors (Q1 and Q2 in Figure 22) are off. Any
overlap in Q1 and Q2 conduction will result in large cur-
rents flowing through the power devices between the
high and low voltage motor rails.
To minimize dead time the designer must consider the
propagation delay characteristics of the optocoupler as
well as the characteristics of the IPM IGBT gate drive cir-
cuit. Considering only the delay characteristics of the op-
tocoupler (the characteristics of the IPM IGBT gate drive
circuit can be analyzed in the same way) it is important
to know the minimum and maximum turn-on (t
turn-off (t
ably over the desired operating temperature range.
The limiting case of zero dead time occurs when the in-
put to Q1 turns off at the same time that the input to Q2
turns on. This case determines the minimum delay be-
tween LED1 turn-off and LED turn-on, which is related
to the worst case optocoupler propagation delay wave-
forms, as shown in Figure 23. A minimum dead time of
zero is achieved in Figure 23 when the signal to turn on
LED is delayed by (t
Figure 2. Typical Transfer Characteristics.
8
PLH
) propagation delay specifications, prefer-
PLH max
- t
PHL min
) from the LED1 turn
PHL
) and
off. Note that the propagation delays used to calculate
PDD are taken at equal temperatures since the optocou-
plers under consideration are typically mounted in close
proximity to each other. (Specifically, t
in the previous equation are not the same as the t
and t
specified in the data sheet.) This delay is the maximum
value for the propagation delay difference specification
which is specified at 370 ns for the ACPL-M46T over an
operating temperature range of -40°C to 125°C.
Delaying the LED signal by the maximum propagation
delay difference ensures that the minimum dead time is
zero, but it does not tell a designer what the maximum
dead time will be. The maximum dead time occurs in
the highly unlikely case where one optocoupler with
the fastest t
the same inverter leg. The maximum dead time in this
case becomes the sum of the spread in the t
propagation delays as shown in Figure 24. The maximum
dead time is also equivalent to the difference between
the maximum and minimum propagation delay differ-
ence specifications. The maximum dead time (due to the
optocouplers) for the ACPL-M46T is 520 ns (= 370 ns -
(-150 ns)) over an operating temperature range of -40°C
to 125°C.
Figure 3. Normalized Output Current vs. Temperature.
PHL min
, over the full operating temperature range,
PLH
and another with the slowest t
PLH max
PLH
and t
PHL
and t
PLH max
PHL min
are in
PHL