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参数资料
| 型号： | MAX9814ETD+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 14/14页 |
| 文件大小： | 0K |
| 描述： | IC AMP AUDIO MONO AB MIC 14TDFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 类型： | AB 类 |
| 输出类型： | 1-通道（单声道） |
| 电源电压： | 2.7 V ~ 5.5 V |
| 特点： | AGC，麦克风，关机 |
| 安装类型： | 表面贴装 |
| 供应商设备封装： | 14-TDFN-EP（3x3） |
| 封装/外壳： | 14-WFDFN 裸露焊盘 |
| 包装： | 标准包装 |
| 产品目录页面： | 1392 (CN2011-ZH PDF) |
| 其它名称： | MAX9814ETD+TDKR |
Setting the AGC Threshold
To set the output-voltage threshold at which the micro-
phone output is clamped, an external resistor-divider
must be connected from MICBIAS to ground with the out-
put of the resistor-divider applied to TH. The voltage VTH
determines the peak output-voltage threshold at which
the output becomes clamped. The maximum signal
swing at the output is then limited to two times VTH and
remains at that level until the amplitude of the input signal
is reduced. To disable AGC, connect TH to MICBIAS.
Microphone Bias Resistor
MICBIAS is capable of sourcing 20mA. Select a value for
RMICBIAS that provides the desired bias current for the
electret microphone. A value of 2.2k
Ω is usually sufficient
for a microphone of typical sensitivity. Consult the micro-
phone data sheet for the recommended bias resistor.
Bias Capacitor
The BIAS output of the MAX9814 is internally buffered
and provides a low-noise bias. Bypass BIAS with a
470nF capacitor to ground.
Input Capacitor
The input AC-coupling capacitor (CIN) and the input
resistance (RIN) to the microphone amplifier form a
highpass filter that removes any DC bias from an input
signal (see the
Typical Application Circuit/Functional
Diagram). CIN prevents any DC components from the
input-signal source from appearing at the amplifier out-
puts. The -3dB point of the highpass filter, assuming
zero source impedance due to the input signal source,
is given by:
Choose CIN such that f-3dB_IN is well below the lowest
frequency of interest. Setting f-3dB_IN too high affects the
amplifier’s low-frequency response. Use capacitors with
low-voltage coefficient dielectrics. Aluminum electrolytic,
tantalum, or film dielectric capacitors are good choices
for AC-coupling capacitors. Capacitors with high-voltage
coefficients, such as ceramics (non-C0G dielectrics), can
result in increased distortion at low frequencies.
Output Capacitor
The output of the MAX9814 is biased at 1.23V. To elimi-
nate the DC offset, an AC-coupling capacitor (COUT)
must be used. Depending on the input resistance (RL)
of the following stage, COUT and RL effectively form a
highpass filter. The -3dB point of the highpass filter,
assuming zero output impedance, is given by:
Shutdown
The MAX9814 features a low-power shutdown mode.
When SHDN goes low, the supply current drops to
0.01A, the output enters a high-impedance state, and
the bias current to the microphone is switched off.
Driving SHDN high enables the amplifier. Do not leave
SHDN unconnected.
Power-Supply Bypassing
and PCB Layout
Bypass the power supply with a 0.1F capacitor to
ground. Reduce stray capacitance by minimizing trace
lengths and place external components as close to the
device as possible. Surface-mount components are
recommended. In systems where analog and digital
grounds are available, connect the MAX9814 to analog
ground.
f
1
2R
C
3dB_OUT
L
OUT
=
××
π
f
1
2R
C
3dB_IN
IN
=
××
π
Microphone Amplifier with AGC and
Low-Noise Microphone Bias
MAX9814
Maxim Integrated
9
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相关代理商/技术参数 |
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| MAX9814EVKIT+ | 功能描述:音频 IC 开发工具 MAX9814 Eval Kit RoHS:否 制造商:Texas Instruments 产品:Evaluation Kits 类型:Audio Amplifiers 工具用于评估:TAS5614L 工作电源电压:12 V to 38 V |
| MAX981CPA | 功能描述:校验器 IC Single Comparator / Reference RoHS:否 制造商:STMicroelectronics 产品: 比较器类型: 通道数量: 输出类型:Push-Pull 电源电压-最大:5.5 V 电源电压-最小:1.1 V 补偿电压（最大值）:6 mV 电源电流（最大值）:1350 nA 响应时间: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SC-70-5 封装:Reel |
| MAX981CPA+ | 功能描述:校验器 IC Single Comparator / Reference RoHS:否 制造商:STMicroelectronics 产品: 比较器类型: 通道数量: 输出类型:Push-Pull 电源电压-最大:5.5 V 电源电压-最小:1.1 V 补偿电压（最大值）:6 mV 电源电流（最大值）:1350 nA 响应时间: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SC-70-5 封装:Reel |
| MAX981CSA | 功能描述:校验器 IC RoHS:否 制造商:STMicroelectronics 产品: 比较器类型: 通道数量: 输出类型:Push-Pull 电源电压-最大:5.5 V 电源电压-最小:1.1 V 补偿电压（最大值）:6 mV 电源电流（最大值）:1350 nA 响应时间: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SC-70-5 封装:Reel |
| MAX981CSA+ | 功能描述:校验器 IC Single Comparator / Reference RoHS:否 制造商:STMicroelectronics 产品: 比较器类型: 通道数量: 输出类型:Push-Pull 电源电压-最大:5.5 V 电源电压-最小:1.1 V 补偿电压（最大值）:6 mV 电源电流（最大值）:1350 nA 响应时间: 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:SC-70-5 封装:Reel |
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