1FEATURES

23• Passes FCC Class B Radiated Emissions with

20 Inches of Cable

• E2S System Reduces EMI while Preserving

Audio Quality and Efficiency

• Output Short Circuit Protection with Auto-

Recovery

• No output Filter Required

• Internally Configured Gain (6dB)

• Low power Shutdown Mode

• Minimum External Components

• Click and Pop Suppression

• Micro-Power Shutdown

• Available in Space-Saving DSBGA Package

APPLICATIONS

• Mobile Phones

• PDAs

• Laptops

KEY SPECIFICATIONS

• Efficiency at 3.6V, 400mW into 8Ω 85% (Typ)

• Efficiency at 5V, 1W into 8Ω 88% (Typ)

• Quiescent Power Supply Current at 5V 3.1mA

• Power Output at VDD = 5V, RL = 4Ω

– THD+N ≤ 10% 2.6W (Typ) auto–

THD+N ≤ 1% 2.1W (Typ)

• Power Output at V DD = 5V, RL = 8Ω

– THD+N ≤ 10% 1.6W (Typ)

– THD+N ≤ 1% 1.3W (Typ)

• Shutdown Current 0.01μA (Typ)

DESCRIPTION

The LM48311 is a single supply, high efficiency,

mono, 2.6W, filterless switching audio amplifier. The

LM48311 features Texas Instruments' Enhanced

Emissions Suppression (E2S) system, that features a

unique patent-pending ultra low EMI, spread

spectrum, PWM architecture, that significantly

reduces RF emissions while preserving audio quality

and efficiency. The E2S system improves battery life,

reduces external component count, board area

consumption, system cost, and simplifying design.

The LM48311 is designed to meet the demands of

portable multimedia devices. Operating from a single

5V supply, the device is capable of delivering 2.6W of

continuous output power to a 4Ω load with less than

10% THD+N. Flexible power supply requirements

allow operation from 2.4V to 5.5V. The LM48311

features both a spread spectrum modulation scheme,

and an advanced, patented edge rate control (ERC)

architecture that significantly reduces emissions,

while maintaining high quality audio reproduction

THD+N = 0.03%) and high efficiency (η = 88%).

The LM48311 features high efficiency compared to

conventional Class AB amplifiers, and other low EMI

Class D amplifiers. When driving and 8Ω speaker

from a 5V supply, the device operates with 88%

efficiency at PO = 1W. The gain of the LM48311 is

internally set to 6dB, further reducing external

component count. A low power shutdown mode

reduces supply current consumption to 0.01μA.

Advanced output short circuit protection with auto–

recovery prevents the device from being damaged

during fault conditions. Superior click and pop

suppression eliminates audible transients on power-

up/down and during shutdown.