LM4875 Datasheet, PDF (1/13 Pages) National Semiconductor (TI) – 750 mW Audio Power Amplifier with DC Volume Control and Headphone Switch

January 2002
LM4875
750 mW Audio Power Amplifier with DC Volume Control
and Headphone Switch
General Description
The LM4875 is a mono bridged audio power amplifier with
DC voltage volume control. The LM4875 is capable of deliv-
ering 750mW of continuous average power into an 8Ω load
with less than 1% THD when powered by a 5V power supply.
Switching between bridged speaker mode and headphone
(single ended) mode is accomplished using the headphone
sense pin. To conserve power in portable applications, the
LM4875’s micropower shutdown mode (I_Q = 0.7µA, typ) is
activated when less than 300mV is applied to the DC Vol/SD
pin.
Boomer audio power amplifiers are designed specifically to
provide high power audio output while maintaining high fidel-
ity. They require few external components and operate on
low supply voltages.
Applications
n GSM phones and accessories, DECT, office phones
n Hand held radio
n Other portable audio devices
Key Specifications
j P_O at 1.0% THD+N into 8Ω
j P_O at 10% THD+N into 8Ω
j Shutdown current
j Supply voltage range
750mW (typ)
1W (typ)
0.7µA(typ)
2.7V to 5.5V
Features
n Precision DC voltage volume control
n Headphone amplifier mode
n “Click and pop” suppression
n Shutdown control when volume control pin is low
n Thermal shutdown protection
Typical Application
Connection Diagram
Small Outline Package (SO)
Mini Small Outline Package (MSOP)
10104202
Top View
Order Number LM4875M, LM4875MM
See NS Package Number M08A, MUA08A
10104201
FIGURE 1. Typical Audio Amplifier
Application Circuit
BOOMER™ is a trademark of National Semiconductor Corporation.
© 2004 National Semiconductor Corporation DS101042
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