LM4838| Datasheet

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LM4838 Stereo 2W Audio Power Amplifiers with DC Volume Control and Selectable Gain

November 2004

LM4838 Stereo 2W Audio Power Amplifiers with DC Volume Control and Selectable Gain
General Description
The LM4838 is a monolithic integrated circuit that provides DC volume control, and stereo bridged audio power amplifiers capable of producing 2W into 4 (Note 1) with less than 1.0% THD or 2.2W into 3 (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 LM4838 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 LM4838 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 LM4838LQ, LM4838MTE, and LM4838GR will deliver 2W into 4. The LM4838MT and LM4838ITL will deliver 1.1W into 8. See Application Information section Exposed-DAP package PCB Mounting Considerations for more information. Note 2: An LM4838LQ and LM4838MTE that have been properly mounted to the circuit board and forced-air cooled will deliver 2.2W into 3.

Key Specifications
n PO at 1% THD+N n into 3 (LQ & MTE) n into 4 (LQ, MTE, GR) n into 8 (MT, MTE, ITL, LQ, & GR) n Single-ended mode - THD+N at 85mW into 32 n Shutdown current 2.2W (typ) 2.0W (typ) 1.1W (typ) 1.0%(typ) 0.7uA (typ)

Features
n n n n n n DC Volume Control Interface System Beep Detect Stereo switchable bridged/single-ended power amplifiers Selectable internal/external gain and bass boost "Click and pop" suppression circuitry Thermal shutdown protection circuitry

Applications
n Portable and Desktop Computers n Multimedia Monitors n Portable Radios, PDAs, and Portable TVs

Block Diagram

20013301

FIGURE 1. LM4838 Block Diagram

Boomer is a registered trademark of NationalSemiconductor Corporation.

2004 National Semiconductor Corporation

DS200133

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