June 2005
LM4954
High Voltage 3 Watt Audio Power Amplifier
General Description
Key Specifications
The LM4954 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 2.4 Watts of continuous average power to an 8Ω
BTL load with less than 1% THD+N from a 7VDC power
supply.
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Wide Power Supply
Voltage Range
2.7 ≤ VDD ≤ 9V
2.4W (typ)
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Output Power: VDD = 7V, 1% THD+N
Quiescent power supply current
PSRR: VDD = 5V and 3V at 217Hz
Shutdown power supply current
3mA (typ)
80dB (typ)
Boomer audio power amplifiers are designed specifically to
provide high quality output power with a minimal number of
external components. The LM4954 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.
0.01µA (typ)
Features
n No output coupling capacitors, snubber networks or
bootstrap capacitors required
n Unity gain stable
n Externally configurable gain
n Ultra low current active low shutdown mode
n BTL output can drive capacitive loads up to 100pF
n “Click and pop” suppression circuitry
n 2.7V - 9.0V operation
The LM4954 features a low-power consumption global shut-
down mode which is achieved by driving the shutdown pin
with logic low. Additionally, the LM4954 features an internal
thermal shutdown protection mechanism.
The LM4954 contains advanced pop & click circuitry which
eliminates noises that would otherwise occur during turn-on
and turn-off transitions.
n Available in space-saving microSMD package
The LM4954 is unity-gain stable and can be configured by
external gain-setting resistors.
Applications
n Mobile Phones
n PDAs
Typical Application
20129111
FIGURE 1. Typical Audio Amplifier Application Circuit
Boomer® is a registered trademark of National Semiconductor Corporation.
© 2005 National Semiconductor Corporation
DS201291
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