LM4894 Datasheet, PDF (1/19 Pages) National Semiconductor (TI) – 1 Watt Fully Differential Audio Power Amplifier With Shutdown Select

June 2003
LM4894
1 Watt Fully Differential Audio Power Amplifier With
Shutdown Select
General Description
The LM4894 is a fully differential audio power amplifier
primarily designed for demanding applications in mobile
phones and other portable communication device applica-
tions. It is capable of delivering 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 LM4894 does not require output
coupling capacitors or bootstrap capacitors, and therefore is
ideally suited for mobile phone and other low voltage appli-
cations where minimal power consumption is a primary re-
quirement.
The LM4894 features a low-power consumption shutdown
mode. To facilitate this, Shutdown may be enabled by either
logic high or low depending on mode selection. Driving the
shutdown mode pin either high or low enables the shutdown
select pin to be driven in a likewise manner to enable Shut-
down. Additionally, the LM4894 features an internal thermal
shutdown protection mechanism.
The LM4894 contains advanced pop & click circuitry which
eliminates noises which would otherwise occur during
turn-on and turn-off transitions.
The LM4894 is unity-gain stable and can be configured by
external gain-setting resistors.
j Power Output at 5.0V & 1% THD
j Power Output at 3.3V & 1% THD
j Shutdown Current
1.0W(typ)
400mW(typ)
0.1µA(typ)
Features
n Fully differential amplification
n Available in space-saving packages micro SMD, MSOP,
and LLP
n Ultra low current shutdown mode
n Can drive capacitive loads up to 500pF
n Improved pop & click circuitry eliminates noises during
turn-on and turn-off transitions
n 2.2 - 5.5V operation
n No output coupling capacitors, snubber networks or
bootstrap capacitors required
n Unity-gain stable
n External gain configuration capability
n Shutdown high or low selectivity
n High CMRR
Applications
n Mobile phones
n PDAs
n Portable electronic devices
Key Specifications
j Improved PSRR at 217Hz
80dB(typ)
Connection Diagrams
Mini Small Outline (MSOP) Package
LLP Package
20013723
Top View
Order Number LM4894MM
See NS Package Number MUB10A
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2003 National Semiconductor Corporation DS200137
20013735
Top View
Order Number LM4894LD
See NS Package Number LDA10B
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