LM48510_0710 Datasheet, PDF (1/20 Pages) National Semiconductor (TI) – Boosted Class D Audio Power Amplifier

October 2007
LM48510
Boosted Class D Audio Power Amplifier
General Description
The LM48510 integrates a boost converter with a high effi-
ciency mono, Class D audio power amplifier to provide 1.2W
continuous power into an 8Ω speaker when operating on a
3.3V power supply with boost voltage (PV₁) of 5.0V. When
operating on a 3.3V power supply, the LM48510 is capable of
driving a 4Ω speaker load at a continuous average output of
1.7W with less than 1% THD+N. The Class D amplifier is a
low noise, filterless PWM architecture that eliminates the out-
put filter, reducing external component count, board area
consumption, system cost, and simplifying design.
The LM48510's switching regulator is a current-mode boost
converter operating at a fixed frequency of 0.6MHz.
The LM48510 is designed for use in mobile phones and other
portable communication devices. The high (76%) efficiency
extends battery life when compared to Boosted Class AB am-
plifiers. The LM48510 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 Class D is externally configurable which allows
independent gain control from multiple sources by summing
the signals. Output short circuit and Thermal shutdown pro-
tection prevent the device from damage during fault condi-
tions. Superior click and pop suppression eliminates audible
transients during power-up and shutdown.
Key Specifications
■ Quiescent Power Supply Current
■ Output Power
(R_L = 8Ω, THD+N ≤ 1%,
V_DD = 3.3V, PV₁ = 5.0V)
■ Shutdown Current
6mA (typ)
1.2W (typ)
0.01μA (typ)
Features
■ ^{Click and Pop Suppression}
■ ^{Low 0.01μA Shutdown Current}
■ ^{76% Efficiency}
■ ^{Filterless Class D}
■ ^{2.7V - 5.0V operation (V}_DD⁾
■ ^{Externally configurable gain on Class D}
■ ^{Very fast turn on time: 17μs}
■ ^{Independent Boost and Amplifier shutdown pins}
Applications
■ ^{Mobile Phones}
■ ^PDAs
■ ^{Portable media}
■ ^Cameras
■ ^{Handheld games}
Typical Application
20123266
FIGURE 1. Typical LM48510 Audio Amplifier Application Circuit
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