LM4817 Datasheet, PDF (1/21 Pages) National Semiconductor (TI) – 1W Stereo Audio Amplifier Plus Adjustable Output Limiter Plus Adjustable LDO

March 2004
LM4817
1W Stereo Audio Amplifier Plus Adjustable Output
Limiter Plus Adjustable LDO
General Description
The LM4817 combines a bridge-connected (BTL) stereo
audio power amplifier with a low dropout voltage regulator
(LDO). The audio amplifier delivers 1.0W to a 8Ω load with a
less than 1.0% THD+N while operating on a 5V power
supply. With V_LIM set to 1.0V, the amplifier outputs are
clamped to 6V_p-p, ±800mV.
With the LM4817’s adjustable low-dropout (LDO) CMOS
linear regulator delivers an output current of up to 300mA,
has shutdown mode (1nA, typ) low quiescent current (90µA,
typ) and LDO voltage (120mV, typ). The regulator is stable
with small ceramic capacitive load (2.2µF, typ). The regulator
includes regulation fault detection, a bandgap voltage refer-
ence, and constant current limiting. It is designed for low
power, low current applications that can take advantage of
its 300mA output current capability.
The LM4817 features an externally controlled micropower
shutdown mode and thermal shutdown protection. It also
utilizes circuitry that reduces "clicks and pops" during device
turn-on and return from shutdown.
Boomer audio power amplifiers are designed specifically to
use few external components and provide high quality output
power in a surface mount package.
Key Specifications
n P_O (BTL): V_DD = 5V, THD+N ≤ 1%, R_L = 8Ω 1.0W(typ)
n Power supply range (amplifier)
3.0V to 5.5V
n Power supply range (LDO)
2.5V to 6.0V
n Shutdown current
0.07µA (typ)
n LDO output current
300mA (min)
n LDO dropout voltage (I_OUT = 300mA)
120mV (typ)
n LDO quiescent supply current
90µA (typ)
n LDO shutdown supply current
1nA (typ)
n LDO PSRR
60dB
n LDO turn-on time
120ms (typ)
n LDO ouput noise-voltage
37µV_RMS (typ)
Features
n Stereo BTL amplifier
n Adjustable output voltage magnitude limiter
n Adjustable LDO regulator
n “Click and pop” suppression circuitry
n LDO is stable with small-value ceramic output capacitors
n Unity-gain stable audio amplifiers
n LDO has over-current protection
n Thermal shutdown protection circuitry
n TSSOP (MH) package
Applications
n Multimedia monitors
n Portable and desktop computers
n Portable televisions
Connection Diagram
20078129
Top View
Order Number LM4817MH
See NS Package Number MXA28A for TSSOP
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation DS200781
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