Manufacturer Part NumberLM4831VF
DescriptionIC AMP AUDIO PWR 1.5W AB 44LQFP
ManufacturerNational Semiconductor
TypeClass AB
LM4831VF datasheet

Specifications of LM4831VF

Output Type2-Channel (Stereo)Max Output Power X Channels @ Load1.5W x 2 @ 4 Ohm
Voltage - Supply2.7 V ~ 5.5 VFeaturesDepop, Input Multiplexer, Microphone, Shutdown
Mounting TypeSurface MountPackage / Case44-LQFP
Lead Free Status / RoHS StatusContains lead / RoHS non-compliantOther names*LM4831VF
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Multimedia Computer Audio Chip
General Description
The LM4831 is a monolithic integrated circuit that provides a
stereo three input mixer, two stereo input analog multiplexer,
a stereo line out and a dual 1W bridged audio power ampli-
fier. In addition, a low noise microphone preamp is included
The LM4831 is ideal for multimedia computers since it incor-
porates an input mixer, analog multiplexer, and configurable
stereo audio power amplifier, as well as a microphone
preamp stage. This combination allows for all of the analog
audio processing to be enclosed in a 44-pin TQFP package.
The LM4831 features an externally controlled, low-power
consumption shutdown mode, as well as both headphone
and docking station modes. To temporarily override the shut-
down mode and allow audio signals to be amplified, the
LM4831 provides four “beep” pins.
Block Diagram
FIGURE 1. LM4831 Block Diagram
is a registered trademark of National Semiconductor Corporation.
is a registered trademark of National Semiconductor Corporation.
© 2000 National Semiconductor Corporation
Key Specifications
n THD+N at 1W into 8
n Microphone Input Referred Noise
n Supply Current - Bridged Mode
n Shutdown Current
n Stereo 1W audio power amplifier
n “Click and pop” suppression circuitry
n Stereo three input mixer
n Shutdown mode
n Multiple operating modes — bridged, single-ended and
docking station modes
n Internal mux for switching in/out external filter
n Beep circuitry for “wake-up” while in shutdown
n 44 Pin TQFP Packaging
n Portable and Desktop Computers
Connection Diagram
See NS Package Number VEJ44A
August 2000
0.6% (typ)
10µV (typ)
16mA (typ)
2µA (typ)
Top View
Order Number LM4831VF

LM4831VF Summary of contents

  • Page 1

    ... Beep circuitry for “wake-up” while in shutdown n 44 Pin TQFP Packaging Applications n Portable and Desktop Computers Connection Diagram DS100057-1 See NS Package Number VEJ44A DS100057 August 2000 0.6% (typ) 10µV (typ) 16mA (typ) 2µA (typ) DS100057-3 Top View Order Number LM4831VF www.national.com ...

  • Page 2

    ... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Storage Temperature Input Voltage Power Dissipation (Note 3) ESD Susceptibility (Note 4) ESD Susceptibility (Note 5) Junction Temperature Soldering Information Small Outline Package ...

  • Page 3

    Electrical Characteristics (Notes 1, 2) The following specifications apply for V measurements represent the full audio chain from Input A of each channel to their respective output. Limits apply for T = 25˚C. A Symbol Parameter THD Total Harmonic Distortion ...

  • Page 4

    Typical Application www.national.com FIGURE 3. Typical Application Circuit 4 DS100057-2 ...

  • Page 5

    Pin Descriptions VDDA This is the analog power supply pin which powers all internal circuitry, with the exceptions of the output amplifiers and the digital logic in the Beep and Switching circuit sections. This pin should be connected to the ...

  • Page 6

    Pin Descriptions (Continued) PWRDWN This pin is used to power down the entire IC (except BEEP Circuitry). Placing a logic high on the PWRDWN pin will place the LM4831 in a low supply current state. To minimize the shutdown-mode supply ...

  • Page 7

    Pin Descriptions (Continued) MIC+IN This pin is the positive input of the microphone amplifier. The microphone amplifier is typically configured as an inverting amplifier, so this pin should be connected to the BYPASS pin to properly bias the amplifier. Further, ...

  • Page 8

    Typical Performance Characteristic THD+N vs Frequency DS100057-17 THD+N vs Output Power DS100057-14 Power Amplifier Noise Floor DS100057-28 Power Amplifier Crosstalk to Mic www.national.com (Continued) THD+N vs Output Power DS100057-11 THD+N vs Output Power DS100057-15 Power Amplifer Crosstalk, Bridged DS100057-13 Power ...

  • Page 9

    Typical Performance Characteristic Power Dissipation, Bridged DS100057-25 Ouput Power vs Supply Voltage Bridged DS100057-24 Microphone THD+N vs Frequency DS100057-19 (Continued) Power Dissipation, Single-Ended Ouput Power vs Supply Voltage Single-Ended DS100057-27 Microphone THD+N vs Output Level DS100057-18 9 DS100057-26 Output Power ...

  • Page 10

    Typical Performance Characteristic Line Out THD+N vs Frequency DS100057-9 Equalizer Output Noise Floor Application Information GROUNDING Certain grounding techniques should be followed when lay- ing out the LM4831 circuit. Figure 4 shows how to setup the grounds for the LM4831. ...

  • Page 11

    Application Information sible. For low frequency considerations, a 10µF or greater tantalum or electrolytic capacitor should be paralleled with the high frequency bypass capacitor. If power supply bypass capacitors are not sufficiently large, the current in the power supply leads, ...

  • Page 12

    Application Information LM4831. The microphone input pin is connected to the in- verting node of a CMOS op amp, so the input impedance is > very high ( 10M ) BEEP CIRCUITRY The beep circuitry is designed to allow a ...

  • Page 13

    ... National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications. inches (millimeters) unless otherwise noted 44-Lead Thin Quad Flat Package Order Number LM4831VF NS Package Number VEJ44A 2. A critical component is any component of a life ...