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參數(shù)資料
| 型號： | LM4873MDC |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 音頻／視頻放大 |
| 英文描述： | 1.1 W, 2 CHANNEL, AUDIO AMPLIFIER, UUC |
| 封裝： | DIE |
| 文件頁數(shù)： | 6/29頁 |
| 文件大?。?/td> | 1019K |
| 代理商： | LM4873MDC |
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Application Information (Continued)
power. The LM4873LQ achieves the same output power
level without forced air cooling. In all circumstances and
conditions, the junction temperature must be held below
150C to prevent activating the LM4873’s thermal shutdown
protection. The LM4873’s power de-rating curve in the Typi-
cal Performance Characteristics shows the maximum
power dissipation versus temperature. Example PCB layouts
for the exposed-DAP TSSOP and LQ packages are shown in
the Demonstration Board Layout section. Further detailed
and specific information concerning PCB layout, fabrication,
and mounting an LQ (LLP) package is available from Na-
tional Semiconductor’s AN1187.
PCB LAYOUT AND SUPPLY REGULATION
CONSIDERATIONS 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
decreases with increasing load current. Reduced supply
voltage causes decreased headroom, output signal clipping,
and reduced output power. Even with tightly regulated sup-
plies, trace resistance creates the same effects as poor
supply regulation. Therefore, making the power supply
traces as wide as possible helps maintain full output voltage
swing.
BRIDGE CONFIGURATION EXPLANATION
As shown in Figure 2, the LM4873 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 LM4873
drives a load, such as a speaker, connected between the two
amplifier outputs, OUTA and +OUTA.
Figure 2 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 * (Rf/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
10099331
* Refer to the section Selecting Proper External Components, for a detailed discussion of CB size.
FIGURE 2. Typical Audio Amplifier Application Circuit
Pin out shown for the 28-pin Expoased-DAP TSSOP package. Refer to the Connection Diagrams for the pin out of the
20-pin Exposed-DAP TSSOP, Exposed-DAP LLP, and micro SMD package.
LM4873
www.national.com
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| LM4873MWC | 1.1 W, 2 CHANNEL, AUDIO AMPLIFIER, UUC |
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| LM4875MMX/NOPB | 1 CHANNEL(S), VOLUME CONTROL CIRCUIT, PDSO8 |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM4873MT | 制造商:Texas Instruments 功能描述: |
| LM4873MT/NOPB | 功能描述:IC AMP AUDIO PWR 3W STER 20TSSOP RoHS:是 類別:集成電路 (IC) >> 線性 - 音頻放大器 系列:Boomer® 產(chǎn)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(yīng)商設(shè)備封裝:25-WLP（2.09x2.09） 封裝/外殼:25-WFBGA，WLCSP 包裝:帶卷 (TR) |
| LM4873MTE | 制造商:Rochester Electronics LLC 功能描述: 制造商:Texas Instruments 功能描述: |
| LM4873MTE/NOPB | 功能描述:音頻放大器 Dual 2.1W Audio Amp Plus Stereo HdPh Fcn 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: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| LM4873MTE-1 | 功能描述:IC AMP AUDIO PWR 3W STER 28TSSOP RoHS:是 類別:集成電路 (IC) >> 線性 - 音頻放大器 系列:Boomer® 產(chǎn)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(yīng)商設(shè)備封裝:25-WLP（2.09x2.09） 封裝/外殼:25-WFBGA，WLCSP 包裝:帶卷 (TR) |
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