參數(shù)資料
型號(hào)： LM4866MTE
廠商： NATIONAL SEMICONDUCTOR CORP
元件分類： 音頻／視頻放大
英文描述： 2.2W Stereo Audio Amplifier
中文描述： 3.2 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20
封裝： 6.50 X 4.40 MM, 0.90 MM HEIGHT, EXPOSED PAD, TSSOP-20
文件頁(yè)數(shù)： 11/21頁(yè)
文件大?。?/td> 644K
代理商： LM4866MTE
Application Information
(Continued)
BRIDGE CONFIGURATION EXPLANATION
As shown in
Figure 1
, the LM4866 consists of two pairs of
operational amplifiers, forming a two-channel (channelAand
channel B) stereo amplifier. (Though the following discusses
channel A, it applies equally to channel B.) External resistors
R
f
and R
i
set the closed-loop gain of Amp1A, whereas two
internal 20k
resistors set Amp2A’s gain at -1. The LM4866
drives a load, such as a speaker, connected between the two
amplifier outputs, -OUTA and +OUTA.
Figure 1
shows that Amp1A’s output serves as Amp2A’s
input. This results in both amplifiers producing signals iden-
tical in magnitude, but 180 out of phase. Taking advantage
of this phase difference, a load is placed between -OUTA
and +OUTA and driven differentially (commonly referred to
as ’bridge mode’). This results in a differential gain of
A
VD
= 2 x (R
f
/ R
i
)
(1)
Bridge mode amplifiers are different from single-ended am-
plifiers that drive loads connected between a single amplifi-
er’s output and ground. For a given supply voltage, bridge
mode has a distinct advantage over the single-ended con-
figuration: its differential output doubles the voltage swing
across the load. This produces four times the output power
when compared to a single-ended amplifier under the same
conditions. This increase in attainable output power as-
sumes that the amplifier is not current limited or that the
output signal is not clipped. To ensure minimum output sig-
nal clipping when choosing an amplifier’s closed-loop gain,
refer to the
Audio Power Amplifier Design
section.
Another advantage of the differential bridge output is no net
DC voltage across the load. This is accomplished by biasing
channel A’s and channel B’s outputs at half-supply. This
eliminates
the
coupling
capacitor
single-ended amplifiers require. Eliminating an output cou-
pling capacitor in a single-ended configuration forces a
single-supply amplifier’s half-supply bias voltage across the
load. This increases internal IC power dissipation and may
permanently damage loads such as speakers.
that
single
supply,
POWER DISSIPATION
Power dissipation is a major concern when designing a
successful single-ended or bridged amplifier. Equation (2)
states the maximum power dissipation point for a single-
ended amplifier operating at a given supply voltage and
driving a specified output load
P
DMAX
= (V
DD
)
2
/ (2
π
2
R
L
) Single-Ended
(2)
However, a direct consequence of the increased power de-
livered to the load by a bridge amplifier is higher internal
power dissipation for the same conditions.
The LM4866 has two operational amplifiers per channel. The
maximum internal power dissipation per channel operating in
the bridge mode is four times that of a single-ended ampli-
20018601
*
Refer to the section Proper Selection of External Components, for a detailed discussion of C
B
size.
FIGURE 1. Typical Audio Amplifier Application Circuit
Pin out shown for the LLP package. Refer to the Connection Diagrams for the pinout of the TSSOP package.
L
www.national.com
11
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LM4866MTE/NOPB 功能描述:音頻放大器 2.2W Stereo Audio Amp RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
LM4866MTEX 功能描述:音頻放大器 RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
LM4866MTEX/NOPB 功能描述:音頻放大器 RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
LM4866MTEXNOPB 制造商:National Semiconductor 功能描述:Audio Amp Speaker 2-CH Stereo 3.2W Class-AB 20-Pin HTSSOP EP T/R 制造商:National Semiconductor 功能描述:Audio Amp Speaker 2-CH Stereo 3.2W Class-AB 20-Pin TSSOP EP T/R
LM4867 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Output-Transient-Free Dual 2.1W Audop Amplifier Plus No Coupling Capacitor Stereo Headphone Function
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