LM4804 Datasheet, PDF (1/16 Pages) National Semiconductor (TI) – Low Voltage High Power Audio Power Amplifier

March 2005
LM4804
Low Voltage High Power Audio Power Amplifier
General Description
The LM4804 integrates a Boost Converter with an Audio
Power Amplifier to drive voice coil speakers in portable
applications. When powered by a 3V supply, it is capable of
creating 1.8W power dissipation in an 8Ω bridge-tied-load
(BTL) with less than 1% THD+N.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. The LM4804 does not require boot-
strap capacitors, or snubber circuits. Therefore it is ideally
suited for portable applications requiring high output voltage
and minimal size.
The LM4804 features a micro-power shutdown mode. Addi-
tionally, the LM4804 features an internal thermal shutdown
protection mechanism.
The LM4804 contains advanced pop & click circuitry that
eliminates output transients which would otherwise occur
during power or shutdown cycles.
The LM4804 is unity-gain stable. Its closed-loop gain is
determined by the value of external, user selected resistors.
Key Specifications
j Quiescent Power Supply Current
(V_DD = 4.2V, R_L = 8Ω)
j BTL Output Power
(R_L = 8Ω, 2% THD+N, V_DD = 3V)
j Shutdown Current
11mA (typ)
1.8W (typ)
2µA (max)
Features
n Pop & click circuitry eliminates noise during turn-on and
turn-off transitions
n Low, 2µA (max) shutdown current
n Low, 11mA (typ) quiescent current (V_DD = 4.2V, R_L =
8Ω)
n 1.8W mono BTL output, R_L = 8Ω, V_DD = 3V
n Short circuit protection
n Unity-gain stable
n External gain configuration capability
Applications
n Cellphone
n PDA
Connection Diagrams
LM4804LQ (5x5)
LQ Marking
20116784
Top View
Order Number LM4804LQ
See NS Package Number LQA28A
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2005 National Semiconductor Corporation DS201167
20116737
Top View
U = Wafer Fab Code
Z = Assembly Plant Code
XY = Date Code
TT = Die Run Code
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