LM4809MA

Manufacturer Part NumberLM4809MA
DescriptionDual 105mW Headphone Amplifier with Active-Low Shutdown Mode
ManufacturerNational Semiconductor
LM4809MA datasheet
 


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LM4809
Dual 105mW Headphone Amplifier with Active-Low
Shutdown Mode
General Description
The LM4809 is a dual audio power amplifier capable of
delivering 105mW per channel of continuous average power
into a 16Ω load with 0.1% (THD+N) from a 5V power supply.
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. Since the LM4809 does not require
bootstrap capacitors or snubber networks, it is optimally
suited for low-power portable systems.
The unity-gain stable LM4809 can be configured by external
gain-setting resistors.
The LM4809 features an externally controlled, active-low,
micropower consumption shutdown mode, as well as an
internal thermal shutdown protection mechanism.
Typical Application
*Refer to the Application Information Section for information concerning proper selection of the input and output coupling capacitors.
FIGURE 1. Typical Audio Amplifier Application Circuit
Boomer
®
is a registered trademark of National Semiconductor Corporation.
© 2002 National Semiconductor Corporation
Key Specifications
n THD+N at 1kHz at 105mW continuous average power
into 16Ω
n THD+N at 1kHz at 70mW continuous average power
into 32Ω
n Shutdown Current
Features
n Active-low shutdown mode
n "Click and Pop" reduction circuitry
n Low shutdown current
n LLP, MSOP, and SO surface mount packaging
n No bootstrap capacitors required
n Unity-gain stable
Applications
n Headphone Amplifier
n Personal Computers
n Microphone Preamplifier
n PDA’s
DS200090
November 2002
0.1% (typ)
0.1% (typ)
0.4µA (typ)
20009001
www.national.com

LM4809MA Summary of contents

  • Page 1

    ... Application Information Section for information concerning proper selection of the input and output coupling capacitors. FIGURE 1. Typical Audio Amplifier Application Circuit Boomer ® registered trademark of National Semiconductor Corporation. © 2002 National Semiconductor Corporation Key Specifications n THD+N at 1kHz at 105mW continuous average power into 16Ω ...

  • Page 2

    ... Connection Diagrams MSOP Package Top View Order Number LM4809MM See NS Package Number MUA08A SO Package Top View Order Number LM4809MA See NS Package Number M08A LLP Package Top View Order Number LM4809LD See NS Package Number LDA08B www.national.com 20009002 20009002 20009061 2 MSOP Marking 20009066 ...

  • Page 3

    ... 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 ESD Susceptibility (Note 4) ESD Machine model (Note 8) Junction Temperature ( Soldering Information (Note 1) Small Outline Package Vapor Phase (60 sec.) Infrared (15 sec ...

  • Page 4

    Electrical Characteristics The following specifications apply for V Symbol Parameter PSRR Power Supply Rejection Ratio V Shutdown Voltage Input High SDIH V Shutdown Voltage Input Low SDIL Electrical Characteristics The following specifications apply for V Symbol Parameter I Supply Current ...

  • Page 5

    Typical Performance Characteristics THD+N vs Frequency THD+N vs Frequency THD+N vs Frequency 20009003 20009005 20009007 5 THD+N vs Frequency 20009004 THD+N vs Frequency 20009006 THD+N vs Frequency 20009008 www.national.com ...

  • Page 6

    Typical Performance Characteristics THD+N vs Frequency THD+N vs Frequency THD+N vs Output Power www.national.com (Continued) THD+N vs Frequency 20009009 THD+N vs Frequency 20009011 THD+N vs Output Power 20009013 6 20009010 20009012 20009014 ...

  • Page 7

    Typical Performance Characteristics THD+N vs Output Power THD+N vs Output Power THD+N vs Output Power (Continued) THD+N vs Output Power 20009015 THD+N vs Output Power 20009017 THD+N vs Output Power 20009019 7 20009016 20009018 20009020 www.national.com ...

  • Page 8

    Typical Performance Characteristics THD+N vs Output Power Output Power vs Load Resistance Output Power vs Supply Voltage www.national.com (Continued) 20009021 20009023 20009025 8 Output Power vs Load Resistance 20009022 Output Power vs Load Resistance 20009024 Output Power vs Power Supply ...

  • Page 9

    Typical Performance Characteristics Output Power vs Power Supply Power Dissipation vs Output Power Power Dissipation vs Output Power (Continued) 20009027 20009029 20009031 9 Dropout Voltage vs Supply Voltage 20009028 Power Dissipation vs Output Power 20009030 Channel Separation 20009033 www.national.com ...

  • Page 10

    Typical Performance Characteristics Noise Floor Open Loop Frequency Response Open Loop Frequency Response www.national.com (Continued) Power Supply Rejection Ratio 20009034 20009050 20009038 10 20009035 Open Loop Frequency Response 20009051 Supply Current vs Supply Voltage 20009044 ...

  • Page 11

    ... Further detailed and specific information concerning PCB layout, fabrication, and mounting an LD (LLP) package is available from National Semiconductor’s Package Engineer- ing Group under application note AN1187. POWER DISSIPATION Power dissipation is a major concern when using any power amplifier and must be thoroughly understood to ensure a successful design ...

  • Page 12

    Application Information CODECs have outputs of 1V (2.83V RMS the Audio Power Amplifier Design section for more infor- mation on selecting the proper gain. Input and Output Capacitor Value Selection Amplifying the lowest audio frequencies requires high value input and ...

  • Page 13

    Application Information find the minimum supply voltage is to use the Output Power vs Supply Voltage curve in the Typical Performance Char- acteristics section. Another way, using Equation (5 calculate the peak output voltage necessary to achieve the ...

  • Page 14

    Demonstration Board Schematic FIGURE 2. LM4809 Demonstration Board Schematic www.national.com 14 20009057 ...

  • Page 15

    Demonstration Board Layout FIGURE 3. Recommended MSOP PC Board Layout FIGURE 4. Recommended MSOP PC Board Layout FIGURE 5. Recommended MSOP PC Board Layout 20009058 Component-Side Silkscreen 20009059 Component-Side Layout 20009060 Bottom-Side Layout 15 www.national.com ...

  • Page 16

    Demonstration Board Layout www.national.com (Continued) FIGURE 6. Recommended LD PC Board Layout Component-Side Silkscreen FIGURE 7. Recommended LD PC Board Layout Component-Side Layout FIGURE 8. Recommended LD PC Board Layout Bottom-Side Layout 16 20009062 20009063 20009064 ...

  • Page 17

    ... Physical Dimensions inches (millimeters) unless otherwise noted Order Number LM4809MM NS Package Number MUA08A Order Number LM4809MA NS Package Number M08A 17 www.national.com ...

  • Page 18

    ... NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant ...