LM4850LDX

Manufacturer Part NumberLM4850LDX
ManufacturerNational Semiconductor
LM4850LDX datasheet
 


Specifications of LM4850LDX

Operational ClassClass-ABAudio Amplifier FunctionHeadphone/Speaker
Total Harmonic Distortion1@32Ohm@95mW%Single Supply Voltage (typ)3/5V
Dual Supply Voltage (typ)Not RequiredVSupply Current (max)7@5VmA
Power Supply RequirementSingleRail/rail I/o TypeNo
Single Supply Voltage (min)2.4VSingle Supply Voltage (max)5.5V
Dual Supply Voltage (min)Not RequiredVDual Supply Voltage (max)Not RequiredV
Operating Temp Range-40C to 85COperating Temperature ClassificationIndustrial
MountingSurface MountPin Count14
Package TypeLLPLead Free Status / Rohs StatusNot Compliant
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LM4850
Mono 1.5 W / Stereo 300 mW Power Amplifier
General Description
The LM4850 is an audio power amplifier capable of deliver-
ing 1.5W (typ) of continuous average power into a mono 4Ω
bridged-tied load (BTL) with 1% THD+N or 95mW per chan-
nel of continuous average power into stereo 32Ω
single-ended (SE) loads with 1% THD+N, using a 5V power
supply.
The LM4850 can automatically switch between mono BTL
and stereo SE modes utilizing a headphone sense pin. It is
ideal for any system that provides both a monaural speaker
output and a stereo line or headphone output
Boomer audio power amplifiers were designed specifically to
provide high quality output power with a minimal amount of
external components. Since the LM4850 does not require
bootstrap capacitors or snubber networks, it is optimally
suited for low-power portable systems.
The LM4850 features an externally controlled, micropower
consumption shutdown mode and thermal shutdown protec-
tion. The unity-gain stable LM4850’s gain is set by external
gain-setting resistors
Note 1: An LM4850LD that has been properly mounted to a circuit board will
deliver 1.9W into 3Ω (at 1% THD+N). The other package options for the
LM4850 will deliver 1.1W into 8Ω (at 1% THD+N). See Application Infor-
mation sections for further information concerning the LM4850LD,
LM4850MM, and LM4850MT.
Typical Application
FIGURE 1. Typical Audio Amplifier Application Circuit
Boomer
®
is a registered trademark of National Semiconductor Corporation.
© 2002 National Semiconductor Corporation
Key Specifications
n Output Power at 1% THD+N, 1kHz:
LM4850LD 3Ω BTL
n
LM4850LD 4Ω BTL
n
LM4850MM, MT 4Ω BTL
n
LM4850LD, MM, MT 8Ω BTL
n
LM4850LD, MM, MT 8Ω SE
n
LM4850LD, MM, MT 32Ω SE
n
n THD+N at 1kHz, 95mW into 32Ω SE
n Single Supply Operation
n Shutdown Current
Features
n Mono 1.5W BTL or stereo 300mW output
n Headphone sense
n “Click and pop” suppression circuitry
n No bootstrap capacitors required
n Thermal shutdown protection
n Unity-gain stable
n LLP, TSSOP, and MSOP packaging
Applications
n Portable computers
n Desktop computers
n PDA’s
n Handheld games
DS200010
July 2002
1.9W (typ)
1.7W (typ)
1.5W (typ)
1.1W (typ)
300mW (typ)
95mW (typ)
1% (typ)
2.4 to 5.5V
44µA (typ)
20001031
www.national.com

LM4850LDX Summary of contents

  • Page 1

    ... LM4850LD, LM4850MM, and LM4850MT. Typical Application FIGURE 1. Typical Audio Amplifier Application Circuit Boomer ® registered trademark of National Semiconductor Corporation. © 2002 National Semiconductor Corporation Key Specifications n Output Power at 1% THD+N, 1kHz: LM4850LD 3Ω BTL n LM4850LD 4Ω ...

  • Page 2

    Connection Diagrams www.national.com 20001051 Top View 10 Lead MSOP Order Number LM4850MM See NS Package Number MUB10A Top View 14 Lead TSSOP Order Number LM4850MT See NS Package Number MTC14 Top View 14 Lead LLP Order Number LM4850LD See NS ...

  • 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 5) ESD Machine model (Note 8) Junction Temperature ( Solder Information (Note 2) Small Outline Package Vapor Phase (60 sec.) Infrared (15 sec ...

  • Page 4

    Electrical Characteristics The following specifications apply for V Symbol Parameter I Shutdown Current SD V Output Offset Voltage OS P Output Power O V Shutdown Input Voltage High IH V Shutdown Input Voltage Low IL Electrical Characteristics The following specifications ...

  • Page 5

    External Components Description (Refer to Figure 1.) Components 2. C Input coupling capacitor which blocks the DC voltage at the amplifier’s input terminals. Also creates a i highpass filter with R for an explanation of how to determine the value ...

  • Page 6

    Typical Performance Characteristics LD Specific Characteristics LM4850LD Power Dissipation vs Output Power Note 13: This curve shows the LM4850LD’s thermal dissipation ability at different ambient temperatures given the exposed-DAP of the part is soldered to a plane of 1oz. Cu ...

  • Page 7

    Typical Performance Characteristics Non-LD Specific Characteristics THD+N vs Frequency THD+N vs Frequency THD+N vs Output Power (Continued) THD+N vs Frequency 20001067 THD+N vs Output Power 20001039 THD+N vs Output Power 20001041 7 20001068 20001040 20001042 www.national.com ...

  • Page 8

    Typical Performance Characteristics Non-LD Specific Characteristics THD+N vs Output Power THD+N vs Output Power THD+N vs Output Power www.national.com (Continued) THD+N vs Output Power 20001043 THD+N vs Output Power 20001045 Output Power vs Load Resistance 20001047 8 20001044 20001046 20001048 ...

  • Page 9

    Typical Performance Characteristics Non-LD Specific Characteristics Output Power vs Load Resistance Output Power vs Supply Voltage Power Dissipation vs Output Power (Continued) Output Power vs Supply Voltage 20001049 Dropout Voltage vs Supply Voltage 20001071 Power Dissipation vs Output Power 20001055 ...

  • Page 10

    Typical Performance Characteristics Non-LD Specific Characteristics Power Derating Curve Noise Floor Supply Current vs Supply Voltage www.national.com (Continued) 20001057 Open Loop Frequency Response 20001059 Power Supply Rejection Ratio 20001061 10 Channel Separation 20001080 20001062 20001060 ...

  • Page 11

    Typical Performance Characteristics Non-LD Specific Characteristics Application Information BRIDGED AND SINGLE-ENDED OPERATION As shown in Figure 1, the LM4850 contains three operational amplifiers (A1-A3). These amplifiers can be configured for SE or BTL modes. In the SE mode, the LM4850 ...

  • Page 12

    Application Information amplifier’s closed-loop gain without causing excessive out- put signal clipping, please refer to the Audio Power Ampli- fier Design section. A bridge configuration, such as the one used in LM4850, also creates a second advantage over single-ended amplifi- ...

  • Page 13

    Application Information FIGURE 2. Headphone Control Circuit Also shown in Figure 2 are the electrical connections for the headphone jack and plug. A 3-wire plug consists of a Tip, Ring, and Sleave, where the Tip and Ring are audio signal ...

  • Page 14

    Application Information extend to at least one−fifth the lower bandwidth limit and the high frequency response must extend o at least five times the upper bandwidth limit. The variation for both response ± limits is 0.17dB, well within the 0.25dB ...

  • Page 15

    Demonstration Board Layout Recommended LD PC Board Layout: Component-Side SilkScreen FIGURE 3. Recommended LD PC Board Layout: Component-Side Layout FIGURE 4. 15 20001081 20001082 www.national.com ...

  • Page 16

    Demonstration Board Layout www.national.com (Continued) Recommended LD PC Board Layout: Bottom-Side Layout FIGURE 5. Recommended MM PC Board Layout: Component-Side SilkScreen FIGURE 6. 16 20001083 20001093 ...

  • Page 17

    Demonstration Board Layout (Continued) Recommended MM PC Board Layout: Component-Side Layout FIGURE 7. Recommended MM PC Board Layout: Bottom-Side Layout FIGURE 8. 17 20001091 20001092 www.national.com ...

  • Page 18

    Physical Dimensions 14-Lead MOLDED PKG, TSSOP, JEDEC, 4.4mm BODY WIDTH www.national.com inches (millimeters) unless otherwise noted Order Number LM4850MT NS Package Number MTC14 18 ...

  • Page 19

    Physical Dimensions inches (millimeters) unless otherwise noted (Continued) 10-Lead Mini SOIC, 118 Mil Wide, .5MM Pitch PKG Order Number LM4850MM NS Package Number MUB10A 19 www.national.com ...

  • Page 20

    ... 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 ...