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参数资料
| 型号： | MAX9705AETB+T |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 4/18页 |
| 文件大小： | 0K |
| 描述： | IC AMP AUDIO PWR 2.3W D 10TDFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 1 |
| 类型： | D 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： | 2.3W x 1 @ 4 欧姆 |
| 电源电压： | 2.5 V ~ 5.5 V |
| 特点： | 消除爆音，差分输入，短路和热保护，关闭 |
| 安装类型： | 表面贴装 |
| 供应商设备封装： | 10-TDFN-EP（3x3） |
| 封装/外壳： | 10-WFDFN 裸露焊盘 |
| 包装： | 标准包装 |
| 其它名称： | MAX9705AETB+TDKR |
MAX9705
2.3W, Ultra-Low-EMI, Filterless,
Class D Audio Amplifier
12
______________________________________________________________________________________
Click-and-Pop Suppression
The MAX9705 features comprehensive click-and-pop
suppression that eliminates audible transients on start-
up and shutdown. While in shutdown, the H-bridge is in
a high-impedance state. During startup or power-up,
the input amplifiers are muted and an internal loop sets
the modulator bias voltages to the correct levels, pre-
venting clicks and pops when the H-bridge is subse-
quently enabled. For 30ms following startup, a soft-start
function gradually unmutes the input amplifiers.
Applications Information
Filterless Operation
Traditional Class D amplifiers require an output filter to
recover the audio signal from the amplifier’s output. The
filters add cost, increase the solution size of the amplifi-
er, and can decrease efficiency and THD+N perfor-
mance. The traditional PWM scheme uses large
differential output swings (2 x VDD peak-to-peak) and
causes large ripple currents. Any parasitic resistance in
the filter components results in a loss of power, lower-
ing the efficiency.
The MAX9705 does not require an output filter. The
device relies on the inherent inductance of the speaker
coil and the natural filtering of both the speaker and the
human ear to recover the audio component of the
square-wave output. Eliminating the output filter results
in a smaller, less costly, more efficient solution.
Because the frequency of the MAX9705 output is well
beyond the bandwidth of most speakers, voice coil
movement due to the square-wave frequency is very
small. Although this movement is small, a speaker not
designed to handle the additional power can be dam-
aged. For optimum results, use a speaker with a series
inductance >10H. Typical 8
speakers exhibit series
inductances in the 20H to 100H range.
Power-Conversion Efficiency
Unlike a class AB amplifier, the output offset voltage of
a Class D amplifier does not noticeably increase quies-
cent-current draw when a load is applied. This is due to
the power conversion of the Class D amplifier. For exam-
ple, an 8mV DC offset across an 8
load results in 1mA
extra current consumption in a Class AB device. In the
Class D case, an 8mV offset into 8
equates to an addi-
tional power drain of 8W. Due to the high efficiency of
the Class D amplifier, this represents an additional quies-
cent-current draw of 8W/(VDD/100
η), which is on the
order of a few microamps.
Input Amplifier
Differential Input
The MAX9705 features a differential input structure,
making it compatible with many CODECs, and offering
improved noise immunity over a single-ended input
amplifier. In devices such as cellular phones, high-fre-
quency signals from the RF transmitter can be picked
up by the amplifier’s input traces. The signals appear at
the amplifier’s inputs as common-mode noise. A differ-
ential input amplifier amplifies the difference of the two
inputs; any signal common to both inputs is canceled.
Single-Ended Input
The MAX9705 can be configured as a single-ended
input amplifier by capacitively coupling either input to
GND and driving the other input (Figure 5).
Figure 3. MAX9705 Outputs with No Input Signal
VIN = 0V
OUT-
OUT+
VOUT+ - VOUT- = 0V
Figure 4. MAX9705 Efficiency vs. Class AB Efficiency
EFFICIENCY vs. OUTPUT POWER
OUTPUT POWER (W)
EFFICIENCY
(%)
0.8
0.6
0.4
0.2
10
20
30
40
50
60
70
80
90
100
0
01.0
VDD = 3.3V
fIN = 1kHz
RL = 8
CLASS AB
MAX9705
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX9705BEBC | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX9705BEBC+ | 制造商:Maxim Integrated Products 功能描述: |
| MAX9705BEBC+T | 功能描述:音频放大器 2.3W Ultra-Low-EMI Class D Amplifier 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 |
| MAX9705BEBC-T | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX9705BETB+ | 制造商:Maxim Integrated Products 功能描述:AUD AMP SPKR 1CH MONO 2.3W CLS-D 10TDFN EP - Rail/Tube |
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