LM4879 Datasheet, PDF (1/25 Pages) National Semiconductor (TI) – 1.1 Watt Audio Power Amplifier

October 2004
LM4879
1.1 Watt Audio Power Amplifier
General Description
The LM4879 is an audio power amplifier primarily designed
for demanding applications in mobile phones and other por-
table communication device applications. It is capable of
delivering 1.1 watt of continuous average power to an 8Ω
BTL load with less than 1% distortion (THD+N) from a 5V_DC
power supply.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. The LM4879 does not require output
coupling capacitors or bootstrap capacitors, and therefore is
ideally suited for lower-power portable applications where
minimal space and power consumption are primary require-
ments.
The LM4879 features a low-power consumption global shut-
down mode, which is achieved by driving the shutdown pin
with logic low. Additionally, the LM4879 features an internal
thermal shutdown protection mechanism.
The LM4879 contains advanced pop & click circuitry which
eliminates noises which would otherwise occur during
turn-on and turn-off transitions.
The LM4879 is unity-gain stable and can be configured by
external gain-setting resistors.
Key Specifications
j PSRR: 5V, 3V @ 217Hz
j Power Output at 5V & 1% THD+N
j Power Output at 3V & 1% THD+N
j Shutdown Current
62dB (typ)
1.1W (typ)
350mW (typ)
0.1µA (typ)
Features
n No output coupling capacitors, snubber networks or
bootstrap capacitors required
n Unity gain stable
n Ultra low current shutdown mode
n Fast turn on: 80ms (typ), 110ms (max) with 1.0µF
capacitor
n BTL output can drive capacitive loads up to 100pF
n Advanced pop & click circuitry eliminates noises during
turn-on and turn-off transitions
n 2.2V - 5.0V operation
n Available in space-saving µSMD, LLP, and MSOP
packages
Applications
n Mobile Phones
n PDAs
n Portable electronic devices
Typical Application
20024301
FIGURE 1. Typical Audio Amplifier Application Circuit
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation DS200243
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