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参数资料
| 型号： | LM4854LD/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 音频／视频放大 |
| 英文描述： | 0.2 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO14 |
| 封装： | LLP-14 |
| 文件页数： | 11/29页 |
| 文件大小： | 1440K |
| 代理商： | LM4854LD/NOPB |
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Application Information (Continued)
the amplifier that drives the headphone jack’s sleeve. If this
current exceeds 500mA
PK, the amplifier is shutdown, pro-
tecting the LM4854 and the external equipment. For more
information, see the section titled ’Single-Ended Output
Power Performance and Measurement Considerations’.
EXPOSED-DAP MOUNTING CONSIDERATIONS
The LM4854’s exposed-DAP (die attach paddle) package
(LD) provides 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 surrounding
PCB copper area heatsink, copper traces, ground plane, and
finally, surrounding air. The result is a low voltage audio
power amplifier that produces 1.7W dissipation in a 4
load
at
≤ 1% THD+N and over 1.9W in a 3 load at 10% THD+N.
This high power is achieved through careful consideration of
necessary thermal design. Failing to optimize thermal design
may compromise the LM4854’s high power performance and
activate unwanted, though necessary, thermal shutdown
protection.
The LD package must have its DAP soldered to a copper
pad on the PCB. The DAP’s PCB copper pad is then, ideally,
connected to a large plane of continuous unbroken copper.
This plane forms a thermal mass, heat sink, and radiation
area. Place the heat sink area on either outside plane in the
case of a two-sided or multi-layer PCB. (The heat sink area
can also be placed on an inner layer of a multi-layer board.
The thermal resistance, however, will be higher.) Connect
the DAP copper pad to the inner layer or backside copper
heat sink area with 6 (3 X 2) (LD) vias. The via diameter
should be 0.012in - 0.013in with a 1.27mm pitch. Ensure
efficient thermal conductivity by plugging and tenting the vias
with plating and solder mask, respectively.
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 LM4854 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 all circumstances and under all
conditions, the junction temperature must be held below
150C to prevent activating the LM4854’s thermal shutdown
protection. The LM4854’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 LD packages are shown in
the Demonstration Board Layout section. Further detailed
and specific information concerning PCB layout and fabrica-
tion and mounting an LD (LLP) is found in National Semi-
conductor’s AN1187.
20038207
FIGURE 2. Typical Audio Amplifier Application Circuit
LM4854
www.national.com
19
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM4854MM | 制造商:未知厂家 制造商全称:未知厂家 功能描述:AUDIO AMPLIFIER|DUAL|TSSOP|10PIN|PLASTIC |
| LM4854MT | 制造商:Rochester Electronics LLC 功能描述: 制造商:Texas Instruments 功能描述: |
| LM4854MT/NOPB | 功能描述:IC AMP AUDIO PWR 2.3W AB 14TSSOP 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) |
| LM4854MTX/NOPB | 功能描述:IC AMP AUDIO PWR 2.3W AB 14TSSOP 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) |
| LM4855 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:Boomer AUDIO POWER AMPLIFIER Integrated Audio Amplifier System |
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