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參數(shù)資料
| 型號： | LM4863MX/NOPB |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 音頻／視頻放大 |
| 英文描述： | 1.5 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO16 |
| 封裝： | 0.300 INCH, PLASTIC, SOIC-16 |
| 文件頁數(shù)： | 22/22頁 |
| 文件大?。?/td> | 757K |
| 代理商： | LM4863MX/NOPB |
Application Information (Continued)
PCB LAYOUT AND SUPPLY REGULATION CONSIDER-
ATIONS FOR DRIVING 3
AND 4 LOADS
Power dissipated by a load is a function of the voltage swing
across the load and the load’s impedance. As load imped-
ance decreases, load dissipation becomes increasingly de-
pendent on the interconnect (PCB trace and wire) resistance
between the amplifier output pins and the load’s connec-
tions. Residual trace resistance causes a voltage drop,
which results in power dissipated in the trace and not in the
load as desired. For example, 0.1
trace resistance reduces
the output power dissipated by a 4
load from 2.1W to 2.0W.
This problem of decreased load dissipation is exacerbated
as load impedance decreases. Therefore, to maintain the
highest load dissipation and widest output voltage swing,
PCB traces that connect the output pins to a load must be as
wide as possible.
Poor power supply regulation adversely affects maximum
output power. A poorly regulated supply’s output voltage de-
creases with increasing load current. Reduced supply volt-
age causes decreased headroom, output signal clipping,
and reduced output power. Even with tightly regulated sup-
plies, trace resistance creates the same effects as poor sup-
ply regulation. Therefore, making the power supply traces as
wide as possible helps maintain full output voltage swing.
BRIDGE CONFIGURATION EXPLANATION
As shown in
Figure 1, the LM4863 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 in-
ternal 20k
resistors set Amp2A’s gain at -1. The LM4863
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 in-
put. This results in both amplifiers producing signals identical
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 out-
put signal is not clipped. To ensure minimum output signal
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 cou-
DS012881-1
* 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 DIP and SO packages. Refer to the Connection Diagrams for the pinout of the TSSOP,
Exposed-DAP TSSOP, and Exposed-DAP LLP packages.
LM4863
www.national.com
9
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|---|---|
| LM4863MTEX/NOPB | 3.2 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20 |
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| LM4863N/NOPB | 1.5 W, 2 CHANNEL, AUDIO AMPLIFIER, PDIP16 |
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| LM4863N | 功能描述:IC AMP AUDIO PWR 3.2W STER 16DIP RoHS:否 類別:集成電路 (IC) >> 線性 - 音頻放大器 系列:Boomer® 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:DirectDrive® 類型:H 類 輸出類型:耳機，2-通道（立體聲） 在某負載時最大輸出功率 x 通道數(shù)量:35mW x 2 @ 16 歐姆 電源電壓:1.62 V ~ 1.98 V 特點:I²C，麥克風，靜音，短路保護，音量控制 安裝類型:表面貼裝 供應商設備封裝:25-WLP（2.09x2.09） 封裝/外殼:25-WFBGA，WLCSP 包裝:帶卷 (TR) |
| LM4864 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:300 mW Audio Power Amplifier with Shutdown Mode |
| LM4864LD/NOPB | 功能描述:IC AMP AUDIO PWR .725W AB 10LLP RoHS:是 類別:集成電路 (IC) >> 線性 - 音頻放大器 系列:Boomer® 產品培訓模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標準包裝:2,500 系列:DirectDrive® 類型:H 類 輸出類型:耳機，2-通道（立體聲） 在某負載時最大輸出功率 x 通道數(shù)量:35mW x 2 @ 16 歐姆 電源電壓:1.62 V ~ 1.98 V 特點:I²C，麥克風，靜音，短路保護，音量控制 安裝類型:表面貼裝 供應商設備封裝:25-WLP（2.09x2.09） 封裝/外殼:25-WFBGA，WLCSP 包裝:帶卷 (TR) |
| LM4864M | 功能描述:音頻放大器 RoHS:否 制造商:STMicroelectronics 產品: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: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| LM4864M | 制造商:Texas Instruments 功能描述:AMP, AUDIO, BOOMER 0.3W, SMD, SOIC8 制造商:Texas Instruments 功能描述:AMP, AUDIO, BOOMER 0.3W, SMD, SOIC8; Amplifier Class:AB; No. of Channels:1; Output Power:725mW; Supply Voltage Range:2.7V to 5.5V; Amplifier Case Style:MSOP; No. of Pins:8; Load Impedance:8ohm; Operating Temperature Min:-40C; ;RoHS Compliant: Yes |
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