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參數(shù)資料
| 型號(hào)： | MAX9773ETG+ |
| 廠商： | Maxim Integrated Products |
| 文件頁數(shù)： | 5/21頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC AMP AUDIO PWR 1.8W D 24TQFN |
| 標(biāo)準(zhǔn)包裝： | 75 |
| 類型： | D 類 |
| 輸出類型： | 2 通道（立體聲） |
| 在某負(fù)載時(shí)最大輸出功率 x 通道數(shù)量： | 1.8W x 2 @ 4 歐姆 |
| 電源電壓： | 2.6 V ~ 5.5 V |
| 特點(diǎn)： | 消除爆音，差分輸入，短路和熱保護(hù)，關(guān)閉 |
| 安裝類型： | 表面貼裝 |
| 供應(yīng)商設(shè)備封裝： | 24-TQFN-EP（4x4） |
| 封裝/外殼： | 24-WFQFN 裸露焊盤 |
| 包裝： | 管件 |
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.
The theoretical best efficiency of a linear amplifier is
78%; however, that efficiency is only exhibited at peak
output powers. Under normal operating levels (typical
music reproduction levels), efficiency falls below 30%,
whereas the MAX9773 still exhibits >80% efficiencies
under the same conditions (Figure 5).
Shutdown
The MAX9773 has a shutdown mode that reduces power
consumption and extends battery life. Driving SHDN low
places the MAX9773 in a low-power (0.1A) shutdown
mode. Connect SHDN to VDD for normal operation.
Click-and-Pop Suppression
The MAX9773 features comprehensive click-and-pop
suppression that eliminates audible transients on startup
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, preventing
clicks and pops when the H-bridge is subsequently
enabled. For 80ms 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 PWM output.
The filters add cost, increase the solution size of the
amplifier, and can decrease efficiency. The traditional
PWM scheme uses large differential output swings (2 x
VDD(P-P)) and causes large ripple currents. Any parasitic
resistance in the filter components results in a loss of
power, lowering the efficiency.
The MAX9773 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 MAX9773 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, for portable
audio applications, exhibit series inductances in the
range of 20H to 100H.
Output Offset
Unlike a Class AB amplifier, the output offset voltage of a
Class D amplifier does not noticeably increase quiescent
current draw when a load is applied. This is due to the
power conversion of the Class D amplifier. For example,
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 additional
power drain of 8W. Due to the high efficiency of the
Class D amplifier, this represents an additional quiescent
current draw of: 8W/(VDD / 100 x
η), which is on the
order of a few A.
MAX9773
1.8W, Filterless, Ultra-Low EMI,
Stereo Class D Audio Power Amplifier
______________________________________________________________________________________
13
VIN_ = 0V
OUT_-
OUT_+
VOUT_+ - VOUT_- = 0V
Figure 4. MAX9773 Outputs with No Input Signal
EFFICIENCY vs. OUTPUT POWER
MAX9773
fig05
OUTPUT POWER (W)
EFFICIENCY
(%)
0.6
0.5
0.3
0.4
0.2
0.1
10
20
30
40
50
60
70
80
90
100
0
00.7
MAX9773
CLASS AB
VDD = 3.3V
f = 1kHz
RL - 8
Figure 5. MAX9773 Efficiency vs. Class AB Efficiency
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| MAX9773ETG+ | 功能描述:音頻放大器 Integrated Circuits (ICs) 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 |
| MAX9773ETG+T | 功能描述:音頻放大器 Integrated Circuits (ICs) 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 |
| MAX9773EWP+G45 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX9773EWP+TG45 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX9775EBX+G45 | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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