1FEATURES

2• Spread Spectrum Architecture Reduces EMI

• Mono Class D Operation

• No Output Filter Required for Inductive Loads

• Externally Configurable Gain

• Very Fast Turn On Time: 17μs (typ)

• Minimum External Components

• Click and Pop Suppression Circuitry

• Micro-Power Shutdown Mode

• Available in Space-Saving 0.5mm Pitch

DSBGA and WSON Packages

APPLICATIONS

• Mobile Phones

• PDAs

• Portable Electronic Devices

KEY SPECIFICATIONS

• Efficiency at 3.6V, 400mW into 8Ω Speaker:

89% (typ)

• Efficiency at 3.6V, 100mW into 8Ω Speaker:

80% (typ)

• Efficiency at 5V, 1W into 8Ω Speaker: 89%

(typ)

• Quiescent Current, 3.6V Supply: 2.2mA (typ)

• Total Shutdown Power Supply Current: 0.01μA

(typ)

• Single Supply Range: 2.4V to 5.5V

• PSRR, f = 217Hz: 82dB

DESCRIPTION

The LM4675 is a single supply, high efficiency,

2.65W, mono, Class D audio amplifier. A spread

spectrum, filterless PWM architecture reduces EMI

and eliminates the output filter, reducing external

component count, board area consumption, system

cost, and simplifying design.

The LM4675 is designed to meet the demands of

mobile phones and other portable communication

devices. Operating on a single 5V supply, it is

capable of driving a 4Ω 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

compared to a typical Class AB amplifier. With a 3.6V

supply driving an 8Ω speaker, the IC's 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 overload protection prevent the device

from damage during fault conditions.