LM4840 Datasheet, PDF (1/19 Pages) National Semiconductor (TI) – Stereo 2W Audio Power Amplifiers with Digital Volume Control and Input Mux

December 2001
LM4840
Stereo 2W Audio Power Amplifiers
with Digital Volume Control and Input Mux
General Description
The LM4840 is a monolithic integrated circuit that provides
digital volume control and stereo bridged audio power am-
plifiers capable of producing 2W into 4Ω (Note 1) with less
than 1.0% THD or 2.2W into 3Ω (Note 2) with less than 1.0%
THD.
Boomer^® audio integrated circuits were designed specifically
to provide high quality audio while requiring a minimum
amount of external components. The LM4840 incorporates a
digital volume control, stereo bridged audio power amplifiers,
an input mux, and a last volume level memory function to
save the volume setting during shutdown. These features
make it optimally suited for multimedia monitors, portable
radios, desktop, and portable computer applications.
The LM4840 features an externally controlled, low-power
consumption shutdown mode, and both a power amplifier
and headphone mute for maximum system flexibility and
performance.
Note 1: When properly mounted to the circuit board, the LM4840LQ and
LM4840MH will deliver 2W into 4Ω. The LM4840MT will deliver 1.1W into 8Ω.
See the Application Information section LM4840LQ and for LM4840MH us-
age information.
Note 2: An LM4840LQ and LM4840MH that have 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 (LM4840LQ, LM4840MH)
2.2W (typ)
n into 4Ω (LM4840LQ, LM4840MH)
2.0W (typ)
n into 8Ω (LM4840)
1.1W (typ)
n Single-ended mode - THD+N at 85mW into 32Ω 1.0%
(typ)
n Shutdown current
0.2µA (typ)
Features
n PC98 and PC99 Compliant
n Digital Volume Control Interface
n System Beep Detect
n Stereo switchable bridged/single-ended power amplifiers
n “Click and pop” suppression circuitry
n Thermal shutdown protection circuitry
n Input Mux
n Capless headphone drivers
n Last volume memory from shutdown
Applications
n Portable and Desktop Computers
n Multimedia Monitors
n Portable Radios, PDAs, and Portable TVs
Connection Diagram
LLP Package
DS200104-35
Top View
Order Number LM4840LQ
See NS Package Number LQA028A for Exposed-DAP LLP
Boomer^® is a registered trademark of NationalSemiconductor Corporation.
© 2001 National Semiconductor Corporation DS200104
www.national.com