LM48520 Datasheet, PDF (1/18 Pages) National Semiconductor (TI) – Boosted Stereo Class D Audio Power Amplifier with Output Speaker Protection and Spread Spectrum

March 20, 2008
LM48520
Boosted Stereo Class D Audio Power Amplifier with Output
Speaker Protection and Spread Spectrum
General Description
The LM48520 integrates a boost converter with a high effi-
ciency Class D stereo audio power amplifier to provide up to
1W/ch continuous power into an 8Ω speaker when operating
from 2.7V to 5.0V power supply with boost voltage (PV1) of
5.0V. The LM48520 utilizes a proprietary spread spectrum
pulse width modulation technique that lowers RF interference
and EMI levels. The Class D amplifier is a low noise, filterless
PWM architecture that eliminates the output filter, reducing
external component count, board area, power consumption,
system cost, and simplifying design.
The LM48520 is designed for use in mobile phones and other
portable communication devices. The high (78%) efficiency
extends battery life when compared to Boosted Class AB am-
plifiers. The LM48520 features a low-power consumption
shutdown mode. Shutdown may be enabled by driving the
Shutdown pin to a logic low (GND). Also, external leakage is
minimized via control of the ground reference via the SW-
OUT pin .
The LM48520 has 4 gain options which are pin selectable via
Gain0 and Gain1 pins. Output short circuit prevents the de-
vice from damage during fault conditions. 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
11.5mA (typ)
1.1W (typ)
0.04μA (typ)
Features
■ ^{Click and Pop Suppression}
■ ^{Low 0.04μA Shutdown Current}
■ ^{78% Efficiency}
■ ^{Filterless Class D}
■ ^{2.7V - 5.0V operation}
■ ^{4 Adjustable Gain settings}
■ ^{Adjustable output swing limiter with Soft Clipping}
■ ^{Speaker Protection}
■ ^{Short circuit protection on Audio Amps}
■ ^{Independent Boost and Amplifier shutdown pins}
Applications
■ ^{Mobile Phones}
■ ^PDAs
■ ^{Portable media}
■ ^Cameras
■ ^{Handheld games}
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