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参数资料
| 型号： | LMV1024URX |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 音频／视频放大 |
| 英文描述： | PDM Output with Pre-Amplifier for Electret Microphones |
| 中文描述： | 2 CHANNEL, AUDIO AMPLIFIER, PBGA6 |
| 封装： | 0.35 MM, LEAD FREE, MICRO SMD-6 |
| 文件页数： | 5/18页 |
| 文件大小： | 560K |
| 代理商： | LMV1024URX |
20133445
FIGURE 5. Microphone Sensitivity
Microphone with Additional Gain
When gain is added to the electret element, the analog signal
becomes larger and therefore more robust. This can be ac-
complished by using a pre-amplifier with a higher gain then
the JFET. The sensitivity of the microphone consists of the
sensitivity of the electret plus the gain of the pre-amplifier.
When choosing National Semiconductor's LMV1015-15 for
instance, a gain of 15 dB is added by the pre-amplifier. This
results in a sensitivity of 29 dB(V/Pa) with a typical electret
element of 44 dB(V/Pa). National Semiconductor has a wide
range of pre-amplifiers with different gain factors, which can
be used to replace the JFET inside the microphone canister.
Please visit www.national.com for more information on the
LMV1015 and LMV1032 pre-amplifier series. A block diagram
with the LMV1015 pre-amplifier inside an ECM is given in
When taking the same example of busy traffic (70 dB SPL),
the output voltage of the microphone with the LMV1015 is:
Microphone Output = SP + C + S
Where,SP is the Sound Pressure in dB SPLC is the dB SPL
to dBPa conversion (94 dB)S is the Sensitivity in dB(V/Pa)
Microphone output = 70 - 94 - 29 = 53 dBV. This is equivalent
to 6.33 mV
PP.
The pre-amplifier with additional gain reduces the impact of
noise on the wiring / traces from the microphone to the base-
band chip significantly. To minimize interference ultimately,
an Analog-to-Digital converter is integrated in both the
LMV1024/LMV1026, realizing a digital interface between the
microphone and the baseband.
Digital Microphone
By integrating the Analog-to-Digital converter (ADC) in the
LMV1024/LMV1026 all analog signals are kept within the
“shielded” microphone canister. The output is a digital inter-
face that is robust and insensitive to interference and noise
from outside the canister. The output is expressed in dBFS
and therefore the sensitivity is also stated in dB(FS/Pa) in-
stead of dB(V/Pa). To calculate the digital output (Data) in
dBFS the following equation can be written for the LMV1024/
LMV1026:
(1)
Where,
P
REF is the reference power, which is defined as the maximum
allowed input power (Full Scale). P
INPUT is the applied power
on the input pin and “A” is the gain of the pre-amplifier in deci-
bels.
Written into voltages, the equation is:
13
www.national.com
201334 Version 3 Revision 4
Print Date/Time: 2009/07/20 17:12:49
LMV1024/LMV1026
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LMV1024URX/NOPB | 功能描述:IC PRE AMP MIC MONO AB ADC 6USMD RoHS:是 类别:集成电路 (IC) >> 线性 - 音頻放大器 系列:- 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) |
| LMV1026 | 制造商:NSC 制造商全称:National Semiconductor 功能描述:PDM Output with Pre-Amplifier for Electret Microphones |
| LMV1026UR | 制造商:NSC 制造商全称:National Semiconductor 功能描述:PDM Output with Pre-Amplifier for Electret Microphones |
| LMV1026UR/NOPB | 功能描述:IC PRE AMP MIC MONO AB ADC 6USMD RoHS:是 类别:集成电路 (IC) >> 线性 - 音頻放大器 系列:- 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) |
| LMV1026URX | 制造商:NSC 制造商全称:National Semiconductor 功能描述:PDM Output with Pre-Amplifier for Electret Microphones |
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