LM4841 Datasheet, PDF (1/31 Pages) National Semiconductor (TI) – Stereo 2W Amplifiers with DC Volume Control, Transient Free Outputs, and Cap-less Headphone Drive

August 2002
LM4841
Stereo 2W Amplifiers with DC Volume Control,
Transient Free Outputs, and Cap-less Headphone Drive
General Description
The LM4841 is a monolithic integrated circuit that provides
DC volume control and stereo bridged audio power amplifi-
ers capable of producing 2W into 4Ω (Note 1) or 2.2W into
3Ω (Note 2) with less than 1.0% THD.
The LM4841 uses advanced, latest generation circuitry to
eliminate all traces of clicks and pops when the supply
voltages is first applied. The amplifier has a headphone-
amplifier-select input pin that is used to switch the amplifiers
from bridge to single-ended mode for driving headphones. A
new circuit topology eliminates headphone output coupling
capacitors (patent pending).
Boomer^® audio integrated circuits are designed specifically
to provide high quality audio while requiring a minimum
amount of external components. The LM4841 incorporates a
DC volume control, stereo bridged audio power amplifiers
and a selectable gain or bass boost, making it optimally
suited for multimedia monitors, portable radios, desktop, and
portable computer applications.
The LM4841 features an externally controlled, low-power
consumption shutdown mode (Shutdown Low), and both a
power amplifier and headphone mute for maximum system
flexibility and performance.
Note 1: When properly mounted to the circuit board, LM4841MH and
LM4841LQ will deliver 2W into 4Ω. The LM4841MT will deliver 1.1W into 8Ω.
See the Application Information section for LM4841MH usage information.
Note 2: An LM4841MH that has been properly mounted to the circuit board
and forced-air cooled will deliver 2.2W into 3Ω.
Key Specifications
n P_O at 1% THD+N
n into 3Ω (MH and LQ)
n into 4Ω ( MH and LQ)
n into 8Ω (MT, MH, and LQ)
n Single-ended THD+N at 85mW into 32Ω
n Shutdown current
2.2W (typ)
2.0W (typ)
1.1W (typ)
1.0%(typ)
0.7µA (typ)
Features
n Stereo headphone amplifier mode that eliminates the
Output Coupling Capacitors (patent pending)
n Acoustically Enhanced DC Volume Control Taper
n System Beep Detect
n Stereo switchable bridged/single-ended power amplifiers
n Selectable internal/external gain and bass boost
n Advanced “click and pop” suppression circuitry
n Thermal shutdown protection circuitry
Applications
n Portable and Desktop Computers
n Multimedia Monitors
n Portable Radios, PDAs, and Portable TVs
Connection Diagrams
TSSOP Package
20028002
Top View
Order Number LM4841MT or LM4841MH
See NS Package Number MTC28 for TSSOP and MXA28A for Exposed-DAP TSSOP
Boomer^® is a registered trademark of National Semiconductor Corporation.
© 2002 National Semiconductor Corporation DS200280
www.national.com