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參數(shù)資料
| 型號(hào)： | MAX9701 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | 1.3W, Filterless, Stereo Class D Audio Power Amplifier |
| 中文描述： | 1.3W、無(wú)需濾波、立體聲D類音頻功率放大器 |
| 文件頁(yè)數(shù)： | 12/21頁(yè) |
| 文件大?。?/td> | 1322K |
| 代理商： | MAX9701 |
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M
Spread-Spectrum (SSM) Mode
The MAX9701 features a unique, patented spread-
spectrum mode that flattens the wideband spectral
components, improving EMI emissions that may be
radiated by the speaker and cables. This mode is
enabled by setting SYNC = V
DD
(Table 1). In SSM
mode, the switching frequency varies randomly by
±
60kHz around the center frequency (1.2MHz). The
modulation scheme remains the same, but the period
of the sawtooth waveform changes from cycle to cycle
(Figure 2). Instead of a large amount of spectral energy
present at multiples of the switching frequency, the
energy is now spread over a bandwidth that increases
with frequency. Above a few megahertz, the wideband
spectrum looks like white noise for EMI purposes
(Figure 3). A proprietary amplifier topology ensures this
does not corrupt the noise floor in the audio bandwidth.
Synchronous Switching Mode
SYNC
The SYNC input allows the MAX9701 to be synchronized
to a user-defined clock, or another Maxim class D ampli-
fier, creating a fully synchronous system, minimizing
clock intermodulation, and allocating spectral compo-
nents of the switching harmonics to insensitive frequency
bands. Applying a TTL clock signal between 1000kHz
and 1600kHz to SYNC synchronizes the MAX9701. The
period of the SYNC clock can be randomized, allowing
the MAX9701 to be synchronized to another Maxim class
D amplifier operating in SSM mode.
SYNC_OUT
SYNC_OUT allows several MAX9701s as well as other
class D amplifiers (such as the MAX9700) to be cas-
caded. The synchronized output minimizes interfer-
ence due to clock intermodulation caused by the
switching spread between single devices. Using
SYNC_OUT, the modulation scheme remains the same
and audio reproduction is not affected by changing the
switching frequency.
Filterless Modulation/Common-Mode Idle
The MAX9701 uses Maxim’s unique, patented modulation
scheme that eliminates the LC filter required by traditional
class D amplifiers, improving efficiency, reducing compo-
nent count, conserving board space and system cost.
Conventional class D amplifiers output a 50% duty cycle,
180
°
out-of-phase square wave when no signal is pre-
sent. With no filter, the square wave appears across the
load as a DC voltage, resulting in finite load current,
which increases power consumption especially when
idling. When no signal is present at the input of the
MAX9701, the amplifiers will output an in-phase square
wave as shown in Figure 4. Because the MAX9701 drives
the speaker differentially, the two outputs cancel each
other, resulting in no net idle mode voltage across the
speaker, minimizing power consumption.
Efficiency
Efficiency of a class D amplifier is due to the switching
operation of the output stage transistors. In a class D
amplifier, the output transistors act as current-steering
switches and consume negligible additional power.
Any power loss associated with the class D output
stage is mostly due to the I*R loss of the MOSFET on-
resistance, and quiescent-current overhead.
1.3W, Filterless, Stereo Class D Audio
Power Amplifier
12
______________________________________________________________________________________
VIN_ = 0V
OUT_-
OUT_+
VOUT_+ - VOUT_- = 0V
Figure 4. MAX9701 Outputs with No Input Signal
FREQUENCY (MHz)
A
μ
V
280
260
240
200
220
80
100
120
140
160
180
60
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
0.0
30
300
Figure 3. MAX9701 with 76mm of Speaker Cable with TDK
Common-Mode Choke: TDK ACM4532-801-20-X
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| MAX9708 | 20W/40W, Filterless, Spread-Spectrum, Mono/Stereo, Class D Amplifier |
| MAX9708ECB | 20W/40W, Filterless, Spread-Spectrum, Mono/Stereo, Class D Amplifier |
| MAX9708ETN | 20W/40W, Filterless, Spread-Spectrum, Mono/Stereo, Class D Amplifier |
| MAX9712 | 500mW. Low EMI. Filterless. Class D Audio Amplifier |
| MAX9713 | 6W. Filterless. Spread-Spectrum Mono/Stereo Class D Amplifiers |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX9701EBP | 制造商:Maxim Integrated Products 功能描述:1.3W FILTERLESS STEREO CLASS D AU - Rail/Tube |
| MAX9701EBP+ | 制造商:Maxim Integrated Products 功能描述:AUD AMP SPKR 2CH STEREO 2.2W CLS-D 20UCSP - Rail/Tube |
| MAX9701EBP+T | 制造商:Maxim Integrated Products 功能描述:AUD AMP SPKR 2CH STEREO 2.2W CLS-D 20UCSP - Tape and Reel |
| MAX9701EBP+TG45 | 功能描述:音頻放大器 1.3W Filterless Class D Audio 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 |
| MAX9701EBP-T | 制造商:Maxim Integrated Products 功能描述:1.3W, FILTERLESS, STEREO CLASS D AUDIO POWER - Tape and Reel |
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