參數(shù)資料
型號: MAX9742ETX+
廠商: Maxim Integrated Products
文件頁數(shù): 18/36頁
文件大小: 0K
描述: IC AMP AUDIO PWR 20.5W D 36TQFN
標(biāo)準(zhǔn)包裝: 50
類型: D 類
輸出類型: 2 通道(立體聲)
在某負(fù)載時最大輸出功率 x 通道數(shù)量: 20.5W x 2 @ 8 歐姆
電源電壓: 20 V ~ 40 V,±10 V ~ 20 V
特點: 消除爆音,差分輸入,靜音,短路和熱保護(hù),關(guān)機(jī)
安裝類型: 表面貼裝
供應(yīng)商設(shè)備封裝: 36-TQFN 裸露焊盤(6x6)
封裝/外殼: 36-WFQFN 裸露焊盤
包裝: 管件
MAX9742
Single-/Dual-Supply, Stereo 16W,
Class D Amplifier with Differential Inputs
______________________________________________________________________________________
25
speaker loads during mode transitions. After COUT is
charged up to VMID, the MAX9742 concludes the soft-
start sequence by precharging CREGLS, CBOOT, and
CIN. Once the soft-start sequence is complete, the
MAX9742 begins normal operation.
For dual-supply operation, the startup time of the
MAX9742 is primarily dependent on the value of CSFT
since it controls the rate of the soft-start sequencing.
In single-supply operation, the overall startup time is
affected by the values of CMID1, CMID2, CSFT, COUT
(single-ended outputs) and the value of the resistors
used to bias the MID input. This is because soft-start
power-up sequencing is dependent on the charging-up
of the MID input bias network and the charging rate of
COUT. As with dual-supply operation, the startup time is
also affected by the value of CSFT since it controls the
rate of the soft-start sequencing. Using the component
values shown in Figure 11 and a CSFT capacitor value
of 0.22F yields a typical single-supply power-up time
of 1.5s.
For single-supply operation with single-ended outputs,
the leakage current of COUT can also affect the startup
time of the MAX9742. To minimize startup time delays
due to COUT, use capacitors with leakage current rat-
ings less than 1A for COUT.
Supply Pumping Effects
When using the MAX9742 in the single-ended output
configuration, the power-supply voltages (VDD and
VSS) may increase if the supplies cannot sink current.
This “supply pumping” is primarily due to the inductive
loading of the LC filter and the voice coil inductance of
the speaker. The inductive load connected to the out-
put of the device prevents the output current from
changing instantaneously. When the MAX9742 drives
this inductive load, a continuous current flows at the
output whose value is equal to the running average of
the output switching currents, or in other words, the
amplified audio signal. This averaged current continues
to flow during both switching cycles of the half-bridge,
which means that some of the current is pumped back
towards the opposite power supply. If the respective
supply cannot sink this current, it flows into supply
bypass capacitor causing the voltage across the
capacitor to increase.
The amount of current pumped back into the opposite
supply is proportional to the duty cycle of the switching
period. For example, if the magnitude of the average
(continuous) current during a single switching cycle is
equal to -1A and the duty cycle of the output is equal to
25%, this means the VSS supply provides 0.75A of cur-
rent while the VDD supply must sink 0.25A. Since the
VDD supply cannot sink this current, it flows into the
bypass capacitor causing the VDD supply voltage to be
pumped up. Figures 13a and 13b illustrates the contin-
uous output current flow that causes the supply pump-
ing action.
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MAX9742ETX+ 功能描述:音頻放大器 Stereo 16W Class D Amplifier 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
MAX9742ETX+T 功能描述:音頻放大器 Stereo 16W Class D Amplifier 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
MAX9742EVKIT+ 功能描述:音頻放大器 Evaluation Kit for the MAX9742 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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MAX9744ETH+T 功能描述:音頻放大器 Stereo 20W Class D Amplifier 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