參數(shù)資料
型號(hào)： MAX9791BETI+T
廠商： Maxim Integrated Products
文件頁(yè)數(shù)： 13/34頁(yè)
文件大?。?/td> 0K
描述： IC AMP AUDIO 2.2W STER D 28TQFN
產(chǎn)品培訓(xùn)模塊： Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
標(biāo)準(zhǔn)包裝： 2,500
系列： DirectDrive®
類型： D 類
輸出類型： 2-通道（立體聲）帶立體聲耳機(jī)和超低音器
在某負(fù)載時(shí)最大輸出功率 x 通道數(shù)量： 2.2W x 2 @ 4 歐姆; 180mW x 2 @ 32 歐姆
電源電壓： 4.5 V ~ 5.5 V
特點(diǎn)： 消除爆音，LDO，短路保護(hù)和熱保護(hù)，關(guān)機(jī)
安裝類型： 表面貼裝
供應(yīng)商設(shè)備封裝： 28-TQFN-EP（4x4）
封裝/外殼： 28-WFQFN 裸露焊盤
包裝： 帶卷 (TR)
MAX9791/MAX9792
Windows Vista-Compliant Class D Speaker
Amplifiers with DirectDrive Headphone Amplifiers
20
______________________________________________________________________________________
In addition to active emission limiting, the MAX9791/
MAX9792 feature spread-spectrum modulation that flat-
tens the wideband spectral components. Proprietary
techniques ensure that the cycle-to-cycle variation of the
switching period does not degrade audio reproduction
or efficiency (see the
Typical Operating Characteristics).
In spread-spectrum modulation mode, the switching fre-
quency varies randomly by ±15kHz around the center
frequency (530kHz). The effect is to reduce the peak
energy at harmonics of the switching frequency. Above
10MHz, the wideband spectrum looks like noise for EMI
purposes (see Figure 2).
Speaker Current Limit
When the output current of the speaker amplifier
exceeds the current limit (2A, typ) the MAX9791/
MAX9792 disable the outputs for approximately 100s.
At the end of 100s, the outputs are re-enabled. If the
fault condition still exists, the MAX9791/MAX9792 con-
tinue to disable and re-enable the outputs until the fault
condition is removed.
DirectDrive Headphone Amplifier
Traditional single-supply headphone amplifiers bias the
outputs at a nominal DC voltage (typically half the sup-
ply). Large coupling capacitors are needed to block
this DC bias from the headphone. Without these capac-
itors, a significant amount of DC current flows to the
headphone, resulting in unnecessary power dissipation
and possible damage to both headphone and head-
phone amplifier.
Maxim’s DirectDrive architecture uses a charge pump
to create an internal negative supply voltage. This
allows the headphone outputs of the MAX9791/
MAX9792 to be biased at GND while operating from a
single supply (Figure 3). Without a DC component,
there is no need for the large DC-blocking capacitors.
Instead of two large (220F, typ) capacitors, the
MAX9791/MAX9792 charge pump requires two small
1F ceramic capacitors, conserving board space,
reducing cost, and improving the frequency response
of the headphone amplifier.
The MAX9791/MAX9792 feature a low-noise charge
pump. The nominal switching frequency of 530kHz is
well beyond the audio range, and thus does not inter-
fere with audio signals. The switch drivers feature a
controlled switching speed that minimizes noise gener-
ated by turn-on and turn-off transients. By limiting the
switching speed of the charge pump, the di/dt noise
caused by the parasitic trace inductance is minimized.
CLASS D EMI PLOT
FREQUENCY (MHz)
AMPLITUDE
(dB
V/m)
100
10
15
20
25
30
35
40
5
30
1000
EN55022B LIMIT
Figure 2. EMI with 30cm of Speaker Cable
VDD
VDD/2
GND
CONVENTIONAL AMPLIFIER BIASING SCHEME
DirectDrive AMPLIFIER BIASING SCHEME
+VDD
GND
-VDD
VOUT
Figure 3. Traditional Amplifier Output vs. MAX9791/MAX9792
DirectDrive Output
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX9791CETI+ 功能描述:音頻放大器 Windows Vista Class D Speaker Amp RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
MAX9791CETI+T 功能描述:音頻放大器 Windows Vista Class D Speaker Amp RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
MAX9792AETI+ 功能描述:音頻放大器 Windows Vista Class D Speaker Amp RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
MAX9792AETI+T 功能描述:音頻放大器 Windows Vista Class D Speaker Amp RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
MAX9792AEVKIT+ 功能描述:音頻放大器 Windows Vista-Compliant Class D Speaker Amplifiers with DirectDrive Headphone Amplifiers RoHS:否 制造商:STMicroelectronics 產(chǎn)品:General Purpose Audio Amplifiers 輸出類型:Digital 輸出功率: THD + 噪聲: 工作電源電壓:3.3 V 電源電流: 最大功率耗散: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel
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