LM4681
10Watt Stereo CLASS D Audio Power Amplifier with Stereo Headphone Amplifier and I 2C/SPI Volume Control
General Description
The LM4681is a fully integrated single supply,CLASS D audio power amplifier solution.The LM4681utilizes a pro-prietary balanced pul-width modulation technique that low-ers output noi and THD and improves PSRR when com-pared to conventional pul width modulators.
The LM4681also features a stereo headphone amplifier that delivers 80mW into a 32Ωheadt with l
ess than 0.5%THD.The LM4681’s I 2C/SPI (lectable)volume control has a +30dB to –48dB range when speakers are driven and a range of +13dB to –65dB when headphones are connected.All amplifiers are protected by thermal shutdown.Addition-ally,the high efficiency power amplifiers have output current limit.
With a 8Ωload,the IC’s efficiency for a 6W power level is 85%.The IC features click and pop reduction circuitry that minimizes audible popping during device turn-on and turn-off.The LM4681is available in a 48-lead LLP package,ideal for portable and desktop computer applications.
Key Specifications
n P O at THD+N =10%,A V =30dB,V DD =14V 10W (typ)n THD+N at 1kHz at 1W into 8Ω(Power Amp)0.43%(typ)n Efficiency at 7W into 8Ω85%(min)n Total quiescent power supply current 50mA (typ)n THD+N 1kHz,20mW,32Ω(Headphone)0.02%(typ)n
Single supply range 9.0V to 15.5V
Features
n Pul-width modulator.
n I 2C/SPI (lectable)volume control n Stereo headphone amplifier.
n “Click and pop”suppression circuitry.n Micropower shutdown mode.
n
48lead LLP package (No heatsink required).
Applications
n Flat Panel Displays n Televisions
n Multimedia Monitors
Block Diagram
20118922
Block Diagram for LM4681
BOOMER ™is a trademark of National Semiconductor Corporation.
March 2006
LM468110Watt Stereo CLASS D Audio Power Amplifier with Stereo Headphone Amplifier and I2C/SPI Volume Control
©2006National Semiconductor Corporation
Connection Diagram
LLP Package
20118917
Top View
Order Number LM4681SQ
See NS Package Number SQA048AA
(LLP Package)
L M 4681
2
F i g u r e 1.T y p i c a l A p p l i c a t i o n
20118918
LM4681
3
Absolute Maximum Ratings (Note 2)
If Military/Aerospace specified devices are required,plea contact the National Semiconductor Sales Office/Distributors for availability and specifications.Supply Voltage 16V
Input Voltage
−0.3V to V DD
+0.3V Power Dissipation (Note 3)Internally Limited
ESD Susceptibility(Note 4)2000V ESD Susceptibility (Note 5)200V Junction Temperature (Note 6)150˚C
Storage Temperature −65˚C ≤T A ≤150˚C
Soldering Information
LLP Package
Vapor Pha (60c.)215˚C Infrared (15c.)
220˚C
Operating Ratings (Notes 1,2)
Temperature Range T MIN ≤T A ≤T MAX −40˚C ≤T A ≤+85˚C Supply Voltage
9V ≤V DD ≤15.5V
Thermal Resistance (LLP Package)θJA 28˚C/W θJC
20˚C/W
Electrical Characteristics (Notes 1,2,7)
The following specifications apply for V DD =12V,I 2CV DD =5V,R L =8Ω,LC filter values as shown in Figure 1,unless other-wi specified.Limits apply for T A =25˚C.Symbol Parameter
图片去背景Conditions
LM4681Units Typical Limit V DD Operating Supply Voltage Range 1215.59V (max)V (min)I S Quiescent Power Supply Current,Class D Mode
V IN =0V RMS ,V HPSEL =0V 5070mA (max)I S Quiescent Power Supply Current,Headphone Mode
V IN =0V RMS ,V HPSEL =V DD 2230
mA (max)I SD Quiescent Power Supply Current,Shutdown Mode
V SD =5V
0.1mA R IN Input Resistance in Both Modes 8
k ΩI 2CV DD I 2C /SPI Logic Supply Voltage 5.53V (max)V (min)V IH Minimum High Level Input Voltage
I 2
C/SPI Interface pins
0.7x I 2CV DD V (min)V IL Maximum Low Level Input Voltage
0.3x I 2
CV DD
V (max)V HPIH HP Sen High Input Voltage V DD –1V (min)V HPIL
HP Sen Low Input Voltage
V DD /2V (max)Power Amplifiers P O Maximum Output Power,Per Channel
THD+N ≤1%,f IN =1kHz 6.0 5.3
经典著作
W (min)THD+N ≤10%,V DD =14V,f IN =1kHz
10W P D1Power Dissipation P O =6W/Chan,f IN =1kHz 1.17W E FF1Efficiency
P O =6W/Chan,f IN =1kHz 85%THD+N Harmonic Distortion +Noi P O =1W/Chan,f IN =1kHz 0.11%V NOISE
Output Noi Voltage
R SOURCE =50Ω,C IN =1µF,BW =8Hz to 22kHz,
A-weighted,input referred
10
µV
L M 4681
4
Electrical Characteristics(Notes1,2,7)(Continued)
The following specifications apply for V DD=12V,I2CV DD=5V,R L=8Ω,LC filter values as shown in Figure1,unless other-wi specified.Limits apply for T A=25˚C.
Symbol Parameter Conditions
LM4681
Units Typical Limit
PSRR Power Supply Rejection Ratio V RIPPLE=200mV P-P,
C BYPASS1=10µF,
input referred
f=50Hz
f=60Hz
f=100Hz
f=120Hz
f=1kHz
82
84
92
95
95
dB
Headphone Amplifiers
P O Maximum Power Output Per
Channel
THD+N≤1%,R L=32Ω,
f IN=1kHz
9470
mW
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THD+N Distortion+Noi P O=20mW,R L=32Ω,
f IN=1kHz
北方的冬天0.02%
V NOISE Output Noi Voltage,RMS R IN=50Ω,C IN=1µF,
BW=20Hz to20kHz,R L=32Ω
A-weighted,Input referred
22µV
PSRR Power Supply Rejection Ratio
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(Referred to Input)
200mV,1kHz,V IN=0,R L=32Ω77dB
Electrical Characteristics for Volume Control(Notes1,2) The following specifications apply for V DD=12V.Limits apply for T A=25˚C.
Symbol Parameter Conditions
LM4681
Units
(Limits) Typical
(Note8)
Limit
(Note7)
C RANGE Gain Range Digital Code=Full Scale,No Load
Power Amplifier Headphone Amplifier 30
13
29
12
dB(min)
dB(min)
Digital Code=+1LSB,No Load
Power Amplifier Headphone Amplifier –48
–65
–46
–63
dB(min)
dB(min)
A M Mute Gain Digital Code=0,No Load
Power Amplifier
Headphone Amplifier–76–74
想不到
–74
dB(max)
dB(max)
Note1:All voltages are measured with respect to the ground pin,unless otherwi specified.
Note2:“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.
Note3:For operating at ca temperatures above25˚C,the device must be derated bad on a150˚C maximum junction temperature and a thermal resistance
ofθJA=80˚C/W(junction to ambient).
Note4:Human body model,100pF discharged through a1.5kΩresistor.
Note5:Machine Model220pF−240pF discharged through all pins.
Note6:The operating junction temperature maximum is150˚C.
Note7:Limits are guaranteed to National’s AOQL(Average Outgoing Quality Level).
Note8:Typicals are measured at25˚C and reprent the parametric norm.
LM4681
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