IRS20124SPBF International Rectifier, IRS20124SPBF Datasheet - Page 20

• Manufacturer Part Number: IRS20124SPBF
• Description: IC DIGITAL AUDIO DRIVER 14-SOIC
• Manufacturer: International Rectifier
• Type: MOSFET Driverr

Specifications of IRS20124SPBF

• Applications: Amplifiers, Receivers
• Mounting Type: Surface Mount
• Package / Case: 14-SOIC (3.9mm Width), 14-SOL
• Current, Output: 1
• Current, Output, High Level: 1 A
• Current, Output, Low Level: 1.2 A
• Delay, Propagation, Turn-off: 80 ns
• Delay, Propagation, Turn-on: 80 ns
• Driver Type: Audio
• Package: 14-Lead SOIC
• Package Type: 14-Lead SOIC
• Temperature, Operating: –40 to +124 °C
• Thermal Resistance Junction/ambient: 100 °C/W
• Thermal Resistance, Junction To Ambient: 100 °C/W
• Time, Fall, Turn-off: 35 ns
• Time, Rise, Turn-on: 40 ns
• Time, Turn-off Delay: 80 ns
• Time, Turn-on: 80 ns
• Time, Turn-on Delay: 80 ns
• Voltage, Output, High Level: 1.2 V
• Voltage, Output, Low Level: 0.1 V
• Voltage, Supply: 200 V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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Functional description
Programmable Dead-time
The IRS20124 has an internal deadtime generation
block to reduce the number of external components
in the output stage of a Class D audio amplifier.
Selectable deadtime through the DT/SD pin volt-
age is an easy and reliable function, which re-
quires only two external resistors. The deadtime
generation block is also designed to provide a
constant deadtime interval, independent of V
fluctuations. Since the timings are critical to the
audio performance of a Class D audio amplifier,
the unique internal deadtime generation block is
designed to be immune to noise on the DT/SD
pin and the Vcc pin. Noise-free programmable
deadtime function is available by selecting
deadtime from four preset values, which are opti-
mized and compensated.
How to Determine Optimal Deadtime
Please note that the effective deadtime in an actual
application differs from the deadtime specified in
this datasheet due to finite fall time, t
deadtime value in this datasheet is defined as the
time period from the starting point of turn-off on
one side of the switching stage to the starting
point of turn-on on the other side as shown in Fig.
5. The fall time of MOSFET gate voltage must be
subtracted from the deadtime value in the
datasheet to determine the effective dead time of
a Class D audio amplifier.
(Effective deadtime)
= (Deadtime in datasheet) – (fall time, t
f
)
f
. The
cc
A longer deadtime period is required for a MOSFET
with a larger gate charge value because of the
longer t
always beneficial to achieve better linearity in the
Class D switching stage. However, the likelihood
of shoot-through current increases with narrower
deadtime settings in mass production. Negative
values of effective deadtime may cause excessive
heat dissipation in the MOSFETs, potentially
leading to their serious damage. To calculate the
optimal deadtime in a given application, the fall
time (t
the actual circuit needs to be measured. In
addition, the effective deadtime can also vary with
temperature and device parameter variations.
Therefore, a minimum effective deadtime of 10 ns
is recommended to avoid shoot-through current
over the range of operating temperatures and
supply voltages.
HO (or LO)
LO (or HO)
f
)for both output voltages, HO and LO, in
f
. A shorter effective deadtime setting is
90%
10%
Effective Deadtime
IRS20124S(PbF)
tf
Dead-
time
Effective dead-time
10%
20