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参数资料
| 型号： | LM4863N/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 音频／视频放大 |
| 英文描述： | 1.5 W, 2 CHANNEL, AUDIO AMPLIFIER, PDIP16 |
| 封装： | 0.300 INCH, MDIP-16 |
| 文件页数： | 3/21页 |
| 文件大小： | 1219K |
| 代理商： | LM4863N/NOPB |
External Components Description
(Refer to Figure 1.)
Components
Functional Description
1.
R
i
The Inverting input resistance, along with R
f, set the closed-loop gain. Ri, along with Ci, form a high pass
filter with f
c = 1/(2
πR
iCi).
2.
C
i
The input coupling capacitor blocks DC voltage at the amplifier’s input terminals. C
i, along with Ri, create a
highpass filter with f
c = 1/(2
πR
iCi). Refer to the section, SELECTING PROPER EXTERNAL
COMPONENTS, for an explanation of determining the value of C
i.
3.
R
f
The feedback resistance, along with R
i, set the closed-loop gain.
4.
C
s
The supply bypass capacitor. Refer to the POWER SUPPLY BYPASSING section for information about
properly placing, and selecting the value of, this capacitor.
5.
C
B
The capacitor, C
B, filters the half-supply voltage present on the BYPASS pin. Refer to the SELECTING
PROPER EXTERNAL COMPONENTS section for information concerning proper placement and selecting
C
B’s value.
Application Information
EXPOSED-DAP PACKAGE PCB MOUNTING
CONSIDERATIONS
The LM4863’s exposed-DAP (die attach paddle) packages
(MTE and LQ) provide a low thermal resistance between the
die and the PCB to which the part is mounted and soldered.
This allows rapid heat transfer from the die to the surround-
ing PCB copper traces, ground plane and, finally, surround-
ing air. The result is a low voltage audio power amplifier that
produces 2.2W at
≤ 1% THD with a 4 load. This high power
is achieved through careful consideration of necessary ther-
mal design. Failing to optimize thermal design may compro-
mise the LM4863’s high power performance and activate
unwanted, though necessary, thermal shutdown protection.
The MTE and LQ packages must have their DAPs soldered
to a copper pad on the PCB. The DAP’s PCB copper pad is
connected to a large plane of continuous unbroken copper.
This plane forms a thermal mass and heat sink and radiation
area. Place the heat sink area on either outside plane in the
case of a two-sided PCB, or on an inner layer of a board with
more than two layers. Connect the DAP copper pad to the
inner layer or backside copper heat sink area with 32(4x8)
(MTE) or 6(3x2) (LQ) vias. The via diameter should be
0.012in - 0.013in with a 1.27mm pitch. Ensure efficient ther-
mal conductivity by plating-through and solder-filling the
vias.
Best thermal performance is achieved with the largest prac-
tical copper heat sink area. If the heatsink and amplifier
share the same PCB layer, a nominal 2.5in
2 (min) area is
necessary for 5V operation with a 4
load. Heatsink areas
not placed on the same PCB layer as the LM4863 should be
5in
2 (min) for the same supply voltage and load resistance.
The last two area recommendations apply for 25c ambient
temperature. Increase the area to compensate for ambient
temperatures above 25c. In systems using cooling fans, the
LM4863MTE can take advantage of forced air cooling. With
an air flow rate of 450 linear-feet per minute and a 2.5in
2
exposed copper or 5.0in
2 inner layer copper plane heatsink,
the LM4863MTE can continuously drive a 3
load to full
power. The LM4863LQ 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 LM4863’s thermal shutdown
protection. The LM4863’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 LLP packages are shown
in the Demonstration Board Layout section. Further de-
tailed and specific information concerning PCB layout, fabri-
cation, and mounting an LLP package is available from
National Semiconductor’s package Engineering Group.
When contacting them, ask for "Preliminary Application Note
for the Assembly of the LLP Package on a Printed Circuit
Board, Revision A dated 7/14/00."
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.
LM4863
www.national.com
11
相关PDF资料 |
PDF描述 |
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| LM4863LQX/NOPB | 3.2 W, 2 CHANNEL, AUDIO AMPLIFIER, QCC24 |
| LM4864MDC | 0.55 W, 1 CHANNEL, AUDIO AMPLIFIER, UUC13 |
| LM4864MWC | 0.55 W, 1 CHANNEL, AUDIO AMPLIFIER, UUC13 |
| LM4864N/NOPB | 0.675 W, 1 CHANNEL, AUDIO AMPLIFIER, PDIP8 |
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM4864 | 制造商:NSC 制造商全称: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 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) |
| LM4864M | 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 |
| 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 |
| LM4864M/NOPB | 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 |
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