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參數(shù)資料
| 型號： | MAX9708ECB |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | 音頻／視頻放大 |
| 英文描述： | 20W/40W, Filterless, Spread-Spectrum, Mono/Stereo, Class D Amplifier |
| 中文描述： | 42 W, 1 CHANNEL, AUDIO AMPLIFIER, PDSO64 |
| 封裝： | 10 X 10 MM, 1.40 MM HEIGHT, PLASTIC, MS-026BCD, TQFN-64 |
| 文件頁數(shù)： | 13/24頁 |
| 文件大?。?/td> | 781K |
| 代理商： | MAX9708ECB |
M
20W/40W, Filterless, Spread-Spectrum,
Mono/Stereo, Class D Amplifier
______________________________________________________________________________________
13
TEMP
returns high once the junction temperature cools
below the set threshold minus the thermal hysteresis. If
TEMP
is connected to either
MUTE
or SS, the audio
output resumes. The temperature threshold is set by
the TH0, TH1, and TH2 inputs as shown in Table 1. An
RC filter may be used to eliminate any transient at the
TEMP
output as shown in Figure 3.
Gain Selection
The MAX9708 features four pin-selectable gain settings;
see Table 2.
Operating Modes
Fixed-Frequency Modulation (FFM) Mode
The MAX9708 features three switching frequencies in
the FFM mode (Table 3). In this mode, the frequency
spectrum of the Class D output consists of the funda-
mental switching frequency and its associated harmon-
ics (see the Wideband Output Spectrum graph in the
Typical Operating Characteristics
). Select one of the
three fixed switching frequencies such that the harmon-
ics do not fall in a sensitive band. The switching fre-
quency can be changed at any time without affecting
audio reproduction.
Spread-Spectrum Modulation (SSM) Mode
The MAX9708 features a unique, patented spread-
spectrum (SSM) mode that flattens the wideband spec-
tral components, improving EMI emissions that may be
radiated by the speaker and cables. This mode is
enabled by setting FS1 = FS2 = high. In SSM mode, the
switching frequency varies randomly by ±4% around
the center frequency (200kHz). The modulation scheme
remains the same, but the period of the triangle wave-
form changes from cycle to cycle. 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. SSM mode reduces EMI com-
pared to fixed-frequency mode. This can also help to
randomize visual artifacts caused by radiated or sup-
ply-borne interference in displays.
Synchronous Switching Mode
The MAX9708 SYNCIN input allows the Class D amplifi-
er to switch at a frequency defined by an external clock
frequency. Synchronizing the amplifier with an external
clock source may confine the switching frequency to a
less sensitive band. The external clock frequency range
is from 600kHz to 1.2MHz and can have any duty cycle,
but the minimum pulse must be greater than 100ns.
SYNCOUT is an open-drain clock output for synchro-
nizing external circuitry. Its frequency is four times the
amplifier’s switching frequency, and it is active in either
internal or external oscillator mode.
Figure 3. An RC Filter Eliminates Transient During Switching
Table 1. MAX9708 Junction Temperature
Threshold Setting
TEMP
0.1
μ
F
10k
10k
V
DIGITAL
TO DIGITAL
INPUT
JUNCTION
TEMPERATURE
(°C)
TH2
TH1
TH0
80
90
100
110
120
129
139
150
Low
Low
Low
Low
High
High
High
High
Low
Low
High
High
Low
Low
High
High
Low
High
Low
High
Low
High
Low
High
Table 2. MAX9708 Gain Setting
G1
Low
High
High
Low
G2
High
High
Low
Low
GAIN (dB)
22
25
29.5
36
Table 3. Switching Frequencies
FS1
FS2
SYNCOUT
FREQUENCY (kHz)
MODULATION
0
0
1
1
0
1
0
1
200
250
160
200 ±4
Fixed-Frequency
Fixed-Frequency
Fixed-Frequency
Spread-Spectrum
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相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| MAX9708ECB+D | 制造商:Maxim Integrated Products 功能描述:AUD AMP SPKR 1CH MONO/2CH STEREO 42W/21W CLS-D 64TQFP EP - Rail/Tube |
| MAX9708ECB+TD | 制造商:Maxim Integrated Products 功能描述:AUD AMP SPKR 1CH MONO/2CH STEREO 42W/21W CLS-D 64TQFP EP - Tape and Reel |
| MAX9708ETN | 制造商:Maxim Integrated Products 功能描述:20W/40W FILTERLESS, SPREAD-SPECTRUM, MONO/STE - Rail/Tube |
| MAX9708ETN/V+TD | 制造商:Maxim Integrated Products 功能描述:20W/40W FILTERLESS, SPREAD SPECTRUM, MONO/STEREO, CLASS D AM - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC AMP AUDIO PWR 42W STER 56TQFN 制造商:Maxim Integrated Products 功能描述:Filterless Class D Amp Mono/Stereo |
| MAX9708ETN+ | 制造商:Maxim Integrated Products 功能描述:AUD AMP SPKR 1CH MONO/2CH STEREO 42W/21W CLS-D 56TQFN EP - Rail/Tube |
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