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参数资料
| 型号： | MAX9788EVKIT+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 13/13页 |
| 文件大小： | 0K |
| 描述： | EVALUATION KIT FOR MAX9788 |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 放大器类型： | G 类 |
| 输出类型： | 1-通道（单声道） |
| 在某负载时最大输出功率 x 通道数量： | 2.4W x 1 @ 8 欧姆 |
| 电源电压： | 2.7 V ~ 5.5 V |
| 工作温度： | -40°C ~ 85°C |
| 板类型： | 完全填充 |
| 已用 IC / 零件： | MAX9788 |
| 已供物品： | 板 |
Driving a Ceramic Speaker
Applications that require thin cases, such as today’s
mobile phones, demand that external components
have a small form factor. Dynamic loudspeakers that
use a cone and voice coil typically cannot conform to
the height requirements. The option for these applica-
tions is to use a ceramic/piezoelectric loudspeaker.
Ceramic speakers are much more capacitive than a con-
ventional loudspeaker. Typical capacitance values for
such a speaker can be greater than 1F. High peak-to-
peak voltage drive is required to achieve acceptable
sound pressure levels. The high output voltage require-
ment coupled with the capacitive nature of the speaker
demand that the amplifier supply much more current at
high frequencies than at lower frequencies. Above 10kHz,
the typical speaker impedance can be less than 16
Ω.
The MAX9788 is ideal for driving a capacitive ceramic
speaker. The high charge-pump current limit allows for a
flat frequency response out to 20kHz while maintaining
high output voltage swings. See the Frequency Response
graph in the
Typical Operating Characteristics. Figure 3
shows a typical circuit for driving a ceramic speaker.
A 10
Ω series resistance is recommended between the
amplifier output and the ceramic speaker load to ensure
the output of the amplifier sees some fixed resistance at
high frequencies when the speaker is essentially an
electrical short.
Component Selection
Input-Coupling Capacitor
The AC-coupling capacitors (CIN_) and input resistors
(RIN_) form highpass filters that remove any DC bias
from an input signal (see the
Functional Diagram/
Typical Operating Circuit). CIN_ blocks DC voltages
from the amplifier input. The -3dB point of the highpass
filter, assuming zero source impedance due to the
input signal source, is given by:
Ceramic speakers generally perform best at frequen-
cies greater than 1kHz. Low frequencies can deflect
the piezoelectric speaker element so that high frequen-
cies cannot be properly reproduced. This can cause
distortion in the speaker’s usable frequency band.
Select a CIN so the f-3dB closely matches the low fre-
quency response of the ceramic speaker. Use capaci-
tors 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.
Charge-Pump Capacitor Selection
Use capacitors with an ESR less than 50m
Ω for opti-
mum performance. Low-ESR ceramic capacitors mini-
mize the output resistance of the charge pump. For
best performance over the extended temperature
range, select capacitors with an X7R dielectric.
Flying Capacitor (C1)
The value of the flying capacitor (C1) affects the load
regulation and output resistance of the charge pump. A
C1 value that is too small degrades the device’s ability
to provide sufficient current drive. Increasing the value
of C1 improves load regulation and reduces the charge-
pump output resistance to an extent. Above 1F, the on-
resistance of the switches and the ESR of C1 and C2
dominate. A 4.7F capacitor is recommended.
f
RC
Hz
dB
IN
=
××
()
3
1
2
π
__
MAX9788
14VP-P, Class G Ceramic Speaker Driver
_______________________________________________________________________________________
9
MAX9788
OUT+
RL
OUT-
CLASS G
OUTPUT
STAGE
Figure 3. Driving a Ceramic Speaker
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX9788EVKIT+ | 功能描述:音频 IC 开发工具 MAX9788 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 |
| MAX9788EWP+TG45 | 功能描述:音频放大器 14VP-P Class G Cer Speaker Driver RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel |
| MAX9789AETJ+ | 功能描述:音频放大器 Windows Vista Class AB Speaker Amp RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel |
| MAX9789AETJ+C8A | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX9789AETJ+T | 功能描述:音频放大器 Windows Vista Class AB Speaker Amp RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel |
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