LM4941
1.25Watt Fully Differential Audio Power Amplifier With RF Suppression and Shutdown
General Description
The LM4941is a fully differential audio power amplifier primarily designed for demanding applications in mobile phones and other portable communication device applica-tions.It is capable of delivering 1.25watts of continuous average power to a 8Ωload with less than 1%distortion (THD+N)from a 5V DC power supply.The LM4941does not require output coupling capacitors or bootstrap capacitors,and therefore is ideally suited for mobile phone and other low voltage applications where minimal power consumption is a primary requirement.
The LM4941also features proprietary internal circuitry that suppress the coupling of RF signals into the chip.This is important becau certain types of RF signals (such as GSM)can couple into audio amplifiers in such a way that part of the signal is heard through the speaker.The RF suppression circuitry in the LM4941makes it well-suited for portable applications in which strong RF signals generated by an antenna from or a cellular phone or other portable electronic device may couple audibly into the amplifier.Other features include a low-power consumption shutdown mode,internal thermal shutdown protection,and advanced pop &click circuitry.
Key Specifications
j Improved PSRR at 217Hz
95dB (typ)j Power Output at 5.0V @1%THD (8Ω) 1.25W (typ)j Power Output at 3.3V @1%THD 550mW (typ)j Shutdown Current
0.1µA (typ)
Features
n Improved RF suppression,by up to 20dB over previous designs in lected applications n Fully diff
erential amplification
n Available in space-saving micro SMD package n Ultra low current shutdown mode
n Can drive capacitive loads up to 100pF
n Improved pop &click circuitry eliminates nois during turn-on and turn-off transitions n 2.4-5.5V operation
n No output coupling capacitors,snubber networks or bootstrap capacitors required
Applications
n Mobile phones n PDAs
n Portable electronic devices
Typical Application
Boomer ®is a registered trademark of National Semiconductor Corporation.
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FIGURE 1.Typical Audio Amplifier Application Circuit
June 2006
LM49411.25Watt Fully Differential Audio Power Amplifier With RF Suppression and Shutdown
©2006National Semiconductor Corporation
Connection Diagrams
9Bump micro SMD Package
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什么叫单反相机Top View
Order Number LM4941TM
See NS Package Number TMD09AAA
micro SMD Marking
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Top View X =Date Code V =Die Traceability G =Boomer Family H6=LM4941TM
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Absolute Maximum Ratings(Note2)
If Military/Aerospace specified devices are required, plea contact the National Semiconductor Sales Office/ Distributors for availability and specifications.
Supply Voltage 6.0V Storage Temperature−65˚C to+150˚C Input Voltage−0.3V to V DD+0.3V Power Dissipation(Note3)Internally Limited ESD Susceptibility(Note4)2000V ESD Susceptibility(Note5)200V Junction Temperature150˚C
Thermal Resistance
θJA(TM)100˚C/W Soldering Information
See AN-1187
Operating Ratings
Temperature Range
T MIN≤T A≤T MAX−40˚C≤T A≤85˚C Supply Voltage 2.4V≤V DD≤5.5V
Electrical Characteristics V
DD =5V(Notes1,2)
The following specifications apply for V DD=5V,A V=1,and8Ωload unless otherwi specified.Limits apply for T A=25˚C.
Symbol Parameter Conditions
LM4941
Units
(Limits) Typical Limit
(Note6)(Note7)
蛋挞心怎么做
I DD Quiescent Power Supply Current V IN=0V,no load
V IN=0V,R L=8Ω
1.7
1.7
2.5
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mA(max)
I SD Shutdown Current V SHUTDOWN=GND0.11µA(max)
P o Output Power THD=1%(max);f=1kHz
R L=8Ω 1.25 1.1W(min) THD=10%(max);f=1kHz
R L=8Ω 1.54W
THD+N Total Harmonic Distortion+Noi P o=.7Wrms;f=1kHz.04%
PSRR Power Supply Rejection Ratio V ripple=200mV sine p-p
f=217Hz(Note8)9570
dB(min) f=1kHz(Note8)90
CMRR Common-Mode Rejection Ratio f=217Hz,V CM=200mV pp70dB f=20Hz–20kHz,V CM=200mV pp70dB
V OS Output Offt V IN=0V2mV V SDIH Shutdown Voltage Input High 1.4V(min) V SDIL Shutdown Voltage Input Low0.4V(max) SNR Signal-to-Noi Ratio P O=1W,f=1kHz108dB
T WU Wake-up Time from Shutdown Cbypass=1µF12ms
Electrical Characteristics V
DD =3V(Notes1,2)
The following specifications apply for V DD=3V,A V=1,and8Ωload unless otherwi specified.Limits a
pply for T A=25˚C.
Symbol Parameter Conditions
LM4941
Units
(Limits) Typical Limit
(Note6)(Note7)
I DD Quiescent Power Supply Current V IN=0V,no load
V IN=0V,R L=8Ω
1.6
1.6
2.4
mA(max)
I SD Shutdown Current V SHUTDOWN=GND0.11µA(max)
P o Output Power THD=1%(max);f=1kHz
R L=8Ω0.43W THD=10%(max);f=1kHz
R L=8Ω0.54W
THD+N Total Harmonic Distortion+Noi P o=0.25Wrms;f=1kHz.05%
双面上班族PSRR Power Supply Rejection Ratio V ripple=200mV sine p-p
f=217Hz(Note8)95
dB f=1kHz(Note8)90
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Electrical Characteristics V DD =3V (Notes 1,2)
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The following specifications apply for V DD =3V,A V =1,and 8Ωload unless otherwi specified.Limits apply for T A =25˚C.(Continued)
Symbol Parameter
Conditions
LM4941
Units (Limits)Typical Limit (Note 6)(Note 7)
CMRR Common-Mode Rejection Ratio f =217Hz,V CM =200mV pp 70dB V OS Output Offt
V IN =0V
2
mV (max)V SDIH Shutdown Voltage Input High 1.4V (min)V SDIL Shutdown Voltage Input Low 0.4V (max)T WU
Wake-up Time from Shutdown
Cbypass
8
ms
Note 1:All voltages are measured with respect to the ground pin,unless otherwi specified.
Note 2:Absolute Maximum Ratings indicate limits beyond which damage to the device may occur.Operating Ratings indicate conditions for which the device is functional,but do not guarantee specific performance limits.Electrical Characteristics state DC and AC electrical specifications under particular test conditions which guarantee specific performance limits.This assumes that the device is within the Operating Ratings.Specifications are not guaranteed for parameters where no limit is given,however,the typical value is a good indication of device performance.
Note 3:The maximum power dissipation must be derated at elevated temperatures and is dictated by T JMAX ,θJA ,and the ambient temperature T A .The maximum allowable power dissipation is P DMAX =(T JMAX –T A )/θJA or the number given in Absolute Maximum Ratings,whichever is lower.F
or the LM4941,e power derating curve for additional information.
Note 4:Human body model,100pF discharged through a 1.5k Ωresistor.Note 5:Machine Model,220pF –240pF discharged through all pins.Note 6:Typicals are measured at 25˚C and reprent the parametric norm.
Note 7:Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).Note 8:10Ωterminated input.
Note 9:Data taken with BW =80kHz and A V =1/1except where specified.
External Components Description
(Figure 1)Components Functional Description
亲子教育方法1.C S Supply bypass capacitor which provides power supply filtering.Refer to the Power Supply Bypassing ction for information concerning proper placement and lection of the supply bypass capacitor.
2.C B Bypass pin capacitor which provides half-supply filtering.Refer to the ction,Proper Selection of External Components ,for information concerning proper placement and lection of C B .
3.R i Inverting input resistance which ts the clod-loop gain in conjunction with R f .
4.
R f
Internal feedback resistance which ts the clod-loop gain in conjunction with R i .
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Typical Performance Characteristics
(Note 9)
THD+N vs Output Power V DD =5V,R L =8Ω,f =1kHz
THD+N vs Output Power V DD =3V,R L =8Ω,f =1kHz
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THD+N vs Frequency
V DD
=5V,R L =8Ω,P O =700mW
THD+N vs Frequency
V DD调虎离山的故事
=3V,R L =8Ω,P O =250mW除氧器的作用
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PSRR vs Frequency
V DD
=5V,R L =8Ω,Inputs terminated
PSRR vs Frequency
V DD
=3V,R L =8Ω,Inputs terminated
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Typical Performance Characteristics
(Note 9)(Continued)
CMRR vs Frequency V DD =5V,R L =8Ω
CMRR vs Frequency V DD =3V,R L =8Ω
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PSRR vs Common Mode Voltage V DD =5V,R L =8Ω,f =217Hz PSRR vs Common Mode Voltage V DD =3V,R L =8Ω,f =217Hz
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Power Dissipation vs Output Power
V DD =5V,R L =8ΩPower Dissipation vs Output Power
V DD =3V,R L =8Ω
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