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参数资料
| 型号： | LM4868MTEX/NOPB |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 音频／视频放大 |
| 英文描述： | 3 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20 |
| 封装： | 6.50 X 4.40 MM, 0.90 MM HEIGHT, EXPOSED PAD, PLASTIC, TSSOP-20 |
| 文件页数： | 5/28页 |
| 文件大小： | 792K |
| 代理商： | LM4868MTEX/NOPB |
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Application Information (Continued)
STEREO-INPUT MULTIPLEXER (STEREO MUX)
The LM4868 has two stereo inputs. The MUX CTRL Pin
controls which stereo input is active. As shown in the Truth
Table for Logic Inputs, applying 0V to the MUX CTRL input
activates stereo input 1, whereas applying V
DD to the MUX
CTRL inputs activates stereo input 2. To ensure correct
amplifier operation, unused MUX inputs should be tied to
GND.
Typical LM4868 applications use the MUX to switch between
two stereo input signals. Each stereo channel’s gain can be
tailored to produce the required output signal level by choos-
ing the appropriate input and feedback resistor ratio.
Another configuration uses the MUX to select two different
gains or frequency compensated gains that amplify a single
pair of stereo input signals. Figure 5 shows two different
feedback networks, Network 1 and Network 2. Network 1
produces increasing gain as the input signal’s frequency
decreases. This can be used to compensate a small,
full-range speaker’s low frequency response roll-off. Network
2 sets the gain for an alternate load such as headphones.
The circuit in Figure 6 uses Network 1 when driving external
speakers, switching to Network 2 when headphones are
connected. The normally closed control switch in Figure 6’s
headphone jack connects to the MUX CTRL pin. When
headphones are connected, the LM4868’s internal pull-up
that applies V
DD to the HP-IN and the external 100k
resis-
tor applies V
DD to MUX CTRL pin. Simultaneously applying
these control voltages automatically selects the amplifier
(headphone or bridge) and switches the gain (MUX channel
selection). Alternatively, leaving the MUX CTRL pin indepen-
dently accessible allows a user to select bass boost as
needed. This alternative user-selectable bass-boost scheme
requires connecting equal ratio resistor feedback networks
to each MUX input channel. The value of the resistor in the
RC network is chosen to give a gain that is necessary to
achieve the desired bass-boost.
Switching between the MUX channels may change the input
signal source or the feedback resistor network. During the
channel switching transition, the average voltage level
20026731
FIGURE 4. Typical Audio Amplifier Application Circuit
(Pin out shown for the 24-pin Exposed-DAP LLP package. Numbers in ( ) are for the 20-pin MTE and MT packages.)
20026728
FIGURE 5. Input MUX Example
LM4868
www.national.com
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相关PDF资料 |
PDF描述 |
|---|---|
| LM4868MT/NOPB | 1.5 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20 |
| LM4868MTX/NOPB | 1.5 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20 |
| LM4868LQ/NOPB | 3 W, 2 CHANNEL, AUDIO AMPLIFIER, PQCC24 |
| LM4868LQX/NOPB | 3 W, 2 CHANNEL, AUDIO AMPLIFIER, PQCC24 |
| LM4869MH/NOPB | 2.6 W, 2 CHANNEL, AUDIO AMPLIFIER, PDSO20 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM4869 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:1.9W Differential Input, BTL Output Stereo Audio Amplifier with Selectable Gain and Shutdown |
| LM4869MH | 制造商:NSC 制造商全称:National Semiconductor 功能描述:1.9W Differential Input, BTL Output Stereo Audio Amplifier with Selectable Gain and Shutdown |
| LM4869MH/NOPB | 功能描述:IC AMP AUDIO PWR 2.6W AB 20TSSOP 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) |
| LM4870 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:1.1W Audio Power Amplifier with Shutdown Mode |
| LM4870M | 制造商:Rochester Electronics LLC 功能描述:- Bulk |
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