LM4919

1.5V, Mono 85mW BTL Output, 14mW Stereo Headphone

Audio Amplifier

General Description

The unity gain stable LM4919 is both a mono-BTL audio

power amplifier and a Single Ended (SE) stereo headphone

amplifier. Operating on a single 1.5V supply, the mono BTL

mode delivers 85mW into an 8

Ω load at 1% THD+N. In

Single Ended stereo headphone mode, the amplifier delivers

14mW per channel into a 16

Ω load at 1% THD+N.

With the LM4919 packaged in the MM package, the cus-

tomer benefits include low profile and small size. This pack-

age minimizes PCB area and maximizes output power.

The LM4919 features circuitry that reduces output transients

("clicks" and "pops") during device turn-on and turn-off, an

externally controlled, low-power consumption, active-low

shutdown mode, and thermal shutdown. Boomer audio

power amplifiers are designed specifically to use few exter-

nal components and provide high quality output power in a

surface mount package.

Key Specifications

n

Mono-BTL output power

n

(R

Ω,V

85mW (typ)

n

Stereo Headphone output power

n

(R

Ω,V

14mW (typ)

n

Micropower shutdown current

0.02µA (typ)

n

Supply voltage operating range

n

PSRR 1kHz, V

Ω

72dB (typ)

Features

n

Single-cell 0.9V to 2.5V battery operation

n

BTL mode for mono speaker

n

Single ended headphone operation with coupling

capacitors

n

Unity-gain stable

n

"Click and pop" suppression circuitry

n

Active low micropower shutdown

n

Low current, active-low mute mode

n

Thermal shutdown protection circuitry

Applications

n

Portable one-cell audio products

n

Portable one-cell electronic devices

Typical Application

20082101

FIGURE 1. Block Diagram

May 2004

© 2004 National Semiconductor Corporation

DS200821

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