June 2007

LM48820

Ground-Referenced, Ultra Low Noise, Fixed Gain, 95mW

Stereo Headphone Amplifier

General Description

The LM48820 is a ground referenced, fixed-gain audio power

amplifier capable of delivering 95mW of continuous average

power into a 16

Ω single-ended load, with less than 1% THD

+N from a 3V power supply.

The LM48820 features a new circuit technology that utilizes

a charge pump to generate a negative reference voltage. This

allows the outputs to be biased about ground, thereby elimi-

nating output-coupling capacitors typically used with normal

single-ended loads.

Boomer audio power amplifiers were designed specifically to

provide high quality output power with a minimal number of

external components. The LM48820 does not require output

coupling capacitors or bootstrap capacitors, and therefore is

ideally suited for mobile phone and other portable applica-

tions.

The LM48820 features a low-power consumption shutdown

mode selectable for each channel and a soft start function that

reduces

start-up

current

transients.

Additionally,

the

LM48820 features an internal thermal shutdown protection

mechanism.

The LM48820 contains advanced pop & click circuitry that

eliminates noises which would otherwise occur during turn-on

and turn-off transitions.

The LM48820 has an internal fixed gain of 1.5V/V.

Key Specifications

80dB (typ)

R

95mW (typ)

0.05µA (typ)

1.5V/V (typ)

1.6V to 4.5V

Features

package

turn-on and turn-off transitions

bootstrap capacitors, or gain-setting resistors required

Applications

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