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参数资料
| 型号： | LM4680SD/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 音频／视频放大 |
| 英文描述： | 10 W, 1 CHANNEL, AUDIO AMPLIFIER, DSO14 |
| 封装： | LLP-14 |
| 文件页数： | 11/11页 |
| 文件大小： | 754K |
| 代理商： | LM4680SD/NOPB |
Application Hints (Continued)
OUTPUT STAGE FILTERING
The LM4680 requires a low pass filter connected between
the amplifier’s bridge output and the load. Figure 1 shows
the recommended LC filter. A minimum value of 27H is
recommended. As shown in Figure 1, using the values of the
components connected between the amplifier BTL outputs
and the load achieves a 2nd-order lowpass filter response
with a -3dB cutoff frequency of 25kHz.
THD+N MEASUREMENTS AND OUT OF AUDIO BAND
NOISE
THD+N (Total Harmonic Distortion plus Noise) is a very
important parameter by which all audio amplifiers are mea-
sured. Often it is shown as a graph where either the output
power or frequency is changed over the operating range. A
very important variable in the measurement of THD+N is the
bandwidth-limiting filter at the input of the test equipment.
Class D amplifiers, by design, switch their output power
devices at a much higher frequency than the accepted audio
range (20Hz - 20kHz). Alternately switching the output volt-
age between V
DD and GND allows the LM4680 to operate at
much higher efficiency than that achieved by traditional
Class AB amplifiers. Switching the outputs at high frequency
also increases the out-of-band noise. Under normal circum-
stances the output lowpass filter significantly reduces this
out-of-band noise. If the low pass filter is not optimized for a
given switching frequency, there can be significant increase
in out-of-band noise. THD+N measurements can be signifi-
cantly affected by out-of-band noise, resulting in a higher
than expected THD+N measurement. To achieve a more
accurate measurement of THD, the test equipment’s input
bandwidth of the must be limited. Some common upper filter
points are 22kHz, 30kHz, and 80kHz. The input filter limits
the noise component of the THD+N measurement to a
smaller bandwidth resulting in a more real-world THD+N
value.
Recommended Printed Circuit
Board Layout
Figures 2 through 4 show the recommended two-layer PC
board layout that is optimized for the 14-pin SD-packaged
LM4680 and associated external components. This circuit is
designed for use with an external 12V supply and 8W speak-
ers (or load resistors). This circuit board is easy to use. Apply
12V and ground to the board’s V
DD and GND terminals,
respectively. Connect speakers (or load resistors) between
the board’s -OUT and +OUT terminals. Apply the input signal
to the input pin labeled -IN.
LM4680
www.national.com
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LM4680SDX/NOPB | 功能描述:IC AMP AUDIO PWR 10W MONO 14LLP 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) |
| LM4681 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:10 Watt Stereo CLASS D Audio Power Amplifier with Stereo Headphone Amplifier and I2C/SPI Volume Control |
| LM4681A EB WAF | 制造商:Texas Instruments 功能描述: |
| LM4681SQ | 制造商:NSC 制造商全称:National Semiconductor 功能描述:10 Watt Stereo CLASS D Audio Power Amplifier with Stereo Headphone Amplifier and I2C/SPI Volume Control |
| LM4681SQ/NOPB | 功能描述:IC AMP AUDIO PWR 10W STER 48LLP 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) |
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