参数资料
型号: LM4866LQ/NOPB
厂商: NATIONAL SEMICONDUCTOR CORP
元件分类: 音频/视频放大
英文描述: 3.2 W, 2 CHANNEL, AUDIO AMPLIFIER, PQCC24
封装: LLP-24
文件页数: 3/21页
文件大小: 1013K
代理商: LM4866LQ/NOPB
Application Information (Continued)
BRIDGE CONFIGURATION EXPLANATION
As shown in Figure 1, the LM4866 consists of two pairs of
operational amplifiers, forming a two-channel (channel A and
channel B) stereo amplifier. (Though the following discusses
channel A, it applies equally to channel B.) External resistors
R
f and Ri 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 =2x(Rf /Ri)
(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 that single supply, single-
ended amplifiers require. Eliminating an output coupling ca-
pacitor 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 perma-
nently damage loads such as speakers.
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 =(VDD)
2 /(2
π2 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 CB 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.
LM4866
www.national.com
11
相关PDF资料
PDF描述
LM4866LQX/NOPB 3.2 W, 2 CHANNEL, AUDIO AMPLIFIER, PQCC24
LM4866MTX/NOPB 1.5 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20
LM4868MTE/NOPB 3 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20
LM4868MTEX/NOPB 3 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20
LM4868MT/NOPB 1.5 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20
相关代理商/技术参数
参数描述
LM4866MT 制造商:Texas Instruments 功能描述:AMP AUDIO STEREO 2W SMD SSOP20
LM4866MT/NOPB 功能描述:IC AMP AUDIO PWR 3.2W AB 20TSSOP RoHS:是 类别:集成电路 (IC) >> 线性 - 音頻放大器 系列:Boomer® 产品培训模块:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 标准包装:2,500 系列:DirectDrive® 类型:H 类 输出类型:耳机,2-通道(立体声) 在某负载时最大输出功率 x 通道数量:35mW x 2 @ 16 欧姆 电源电压:1.62 V ~ 1.98 V 特点:I²C,麦克风,静音,短路保护,音量控制 安装类型:表面贴装 供应商设备封装:25-WLP(2.09x2.09) 封装/外壳:25-WFBGA,WLCSP 包装:带卷 (TR)
LM4866MTE 制造商:Texas Instruments 功能描述:AMP AUDIO STEREO 2W SMD TSSOP20
LM4866MTE/NOPB 功能描述:音频放大器 2.2W Stereo Audio Amp RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel
LM4866MTEX 功能描述:音频放大器 RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel