LM4805_0508 Datasheet, PDF (1/19 Pages) National Semiconductor (TI) – Low Voltage High Power Audio Power Amplifier

August 2005
LM4805
Low Voltage High Power Audio Power Amplifier
General Description
The LM4805 is a boosted audio power amplifier designed for
driving 8ohm speakers in portable applications. It delivers at
least 1W continuous power to an 8Ω load from any input
voltage between 3V and 4.6V with less than 2% THD+N.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. The LM4805 does not require boot-
strap capacitors, or snubber circuits. Therefore it is ideally
suited for portable applications requiring high power and
minimal size.
The LM4805 features a low-power consumption shutdown
mode along with an internal thermal shutdown protection
mechanism and short circuit protection.
The LM4805 contains advanced pop & click circuitry that
eliminates noises which would otherwise occur during
turn-on and turn-off transitions. The LM4805 is unity-gain
stable and can be configured by external gain-setting resis-
tors.
Key Specifications
j Quiescent Power Supply Current
(V_DD = 3V)
j Output Power
(V_DD = 3.0V, R_L = 8Ω, THD+N = 2%)
j Shutdown Current
14mA (typ)
1W (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, 14mA (typ) quiescent current
n Unity-gain stable
n External gain configuration capability
Applications
n Cellphone
n PTT (Push To Talk) mobile phones
Connection Diagrams
LM4805LQ (5x5)
LQ Marking
Top View
Order Number LM4805LQ
See NS Package Number LQA28A
20126284
20126256
Top View
U = Wafer Fab
Z = Assembly Plant Code
XY = Date Code
TT = Die Run Code
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2005 National Semiconductor Corporation DS201262
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