参数资料
型号: MAX9722AETE+
厂商: Maxim Integrated Products
文件页数: 6/21页
文件大小: 0K
描述: IC AMP AUDIO .13W STER AB 16TQFN
产品培训模块: Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
标准包装: 100
系列: DirectDrive®
类型: AB 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: 130mW x 2 @ 32 欧姆
电源电压: 2.4 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: 16-TQFN-EP(3x3)
封装/外壳: 16-WFQFN 裸露焊盘
包装: 管件
MAX9722A/MAX9722B
such as the headphone socket used as a line output to
a home hi-fi system. In the upper diagram, any differ-
ence between the two GND references (represented by
VNOISE) causes current to flow through the screen of
cable between the two devices. This can cause noise
pickup at the receiver due to the potential divider
action of the audio screen cable impedance and the
GND wiring of the amplifier.
Introducing impedance between the jack socket and
GND of the notebook helps (as shown in the lower dia-
gram). This has the following effect:
Current flow (from GND potential differences) in the
cable screen is reduced, which is a safety issue.
It allows the MAX9722A/MAX9722B differential sensing
to reduce the GND noise seen by the receiver (amplifier).
The other side effect is that the differential headphone
jack sensing corrects the headphone crosstalk (from
introducing the resistance on the jack GND return).
Only one channel is depicted in Figure 9.
Figure 9 has some example numbers for resistance,
but the audio designer has control over only one series
resistance applied to the headphone jack return. Note
that this resistance can be bypassed for ESD purposes
at frequencies much higher than audio if required. The
upper limit for this added resistance is the amount of
output swing the headphone amplifier tolerates when
driving low-impedance loads. Any headphone return
current appears as a voltage across this resistor.
Piezoelectric Speaker Amplifier
Low-profile piezoelectric speakers can provide quality
sound for portable electronics. However, piezoelectric
speakers typically require large voltage swings
(>8VP-P) across the speaker element to produce usable
sound pressure levels. Power sources in portable
devices are usually low voltage in nature. Operating
from batteries, conventional amplifiers cannot provide
sufficient voltage swing to drive a piezoelectric speak-
er. However, the MAX9722’s DirectDrive architecture
can be configured to drive a piezoelectric speaker with
up to 12VP-P while operating from a single 5V supply.
The stereo MAX9722 features an inverting charge
pump that takes the positive +5V supply and creates a
negative -5V supply. Each output of the MAX9722 can
swing 6VP-P. This may be sufficient to drive a piezo-
electric speaker. If a higher output voltage is desired,
configuring the MAX9722A as a bridge-tied load (BTL)
amplifier (Figure 10) doubles the maximum output
swing as seen by the load to 12VP-P. In a BTL configu-
ration, the right channel of the MAX9722 serves as the
master amplifier, setting the gain of the device, driving
one side of the speaker, and providing signal to the left
channel. The left channel is configured as a unity-gain
follower, inverting the output of the right channel and
driving the other leg of the speaker. Use precision
resistors to set the gain of the left channel to ensure low
distortion and good matching.
The MAX9722 was tested with a Panasonic WM-R57A
piezoelectric speaker, and the resulting THD+N curves
are shown (Figures 11 and 12). Note in both graphs, as
frequency increases, the THD+N increases. This is due
5V, Differential Input, DirectDrive, 130mW
Stereo Headphone Amplifiers with Shutdown
14
______________________________________________________________________________________
MAX9722A
INR
OUTR
INL
OUTL
AUDIO
INPUT
1
μF
10k
Ω
10k
Ω
10k
Ω
10k
Ω
Figure 10. MAX9722 BTL Configuration
TOTAL HARMONIC DISTORTION PLUS
NOISE vs. OUTPUT VOLTAGE
MAX9722
fig11
OUTPUT POWER (mW)
THD+N
(%)
12
10
8
6
4
2
0.0010
0.0100
0.1000
1
10
100
0.0001
014
VDD = 5V
AV = -1V/V
OUTPUTS DRIVING
PIEZOELECTRIC SPEAKER
f = 100Hz
f = 20Hz
f = 1kHz
Figure 11. MAX9722 THD+N vs. Output Voltage
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相关代理商/技术参数
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MAX9722AETE+ 功能描述:音频放大器 DirectDrive 130mW Headphone 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
MAX9722AETE+G 功能描述:IC AMP AUDIO .13W STER AB 16TQFN RoHS:是 类别:集成电路 (IC) >> 线性 - 音頻放大器 系列:DirectDrive® 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)
MAX9722AETE+T 功能描述:音频放大器 DirectDrive 130mW Headphone 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
MAX9722AETE-T 功能描述:音频放大器 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
MAX9722AEUE 制造商:Maxim Integrated Products 功能描述:5V, DIFFERENTIAL INPUT, DIRECTDRIVE, 130MW ST - Rail/Tube