LM4675 Ultra-Low EMI, Filterless, 2.65W, Mono, Class D Audio Power Amplifier with Spread
Class D audio amplifier. A spread spectrum, filterless PWM
tion, system cost, and simplifying design.
phones and other portable communication devices. Operat-
ing on a single 5V supply, it is capable of driving a 4鈩?/div>
speaker load at a continuous average output of 2.2W with
less than 1% THD+N. Its flexible power supply requirements
allow operation from 2.4V to 5.5V. The wide band spread
spectrum architecture of the LM4675 reduces EMI-radiated
emissions due to the modulator frequency.
The LM4675 has high efficiency with speaker loads com-
pared to a typical Class AB amplifier. With a 3.6V supply
driving an 8鈩?speaker, the IC鈥檚 efficiency for a 100mW
power level is 80%, reaching 89% at 400mW output power.
The LM4675 features a low-power consumption shutdown
mode. Shutdown may be enabled by driving the Shutdown
pin to a logic low (GND).
The gain of the LM4675 is externally configurable which
allows independent gain control from multiple sources by
summing the signals. Output short circuit and thermal over-
load protection prevent the device from damage during fault
conditions.
Key Specifications
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Efficiency at 3.6V, 400mW into 8鈩?speaker 89% (typ)
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Efficiency at 3.6V, 100mW into 8鈩?speaker 80% (typ)
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Efficiency at 5V, 1W into 8鈩?speaker
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Quiescent current, 3.6V supply
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Total shutdown power supply current
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Single supply range
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PSRR, f = 217Hz
89% (typ)
2.2mA (typ)
0.01碌A (typ)
2.4V to 5.5V
82dB
Features
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Spread spectrum architecture reduces EMI
Mono Class D Operation
No output filter required for inductive loads
Externally configurable gain
Very fast turn on time: 17碌s (typ)
Minimum external components
"Click and pop" suppression circuitry
Micro-power shutdown mode
Available in space-saving 0.5mm pitch micro SMD and
LLP packages
Applications
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Mobile phones
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PDAs
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Portable electronic devices
20182721
LM4675 Rf Emissions 鈥?6in cable
Boomer
庐
is a registered trademark of National Semiconductor Corporation.
漏 2006 National Semiconductor Corporation
DS201827
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