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參數資料
| 型號： | MAX9700BEVKIT |
| 廠商： | Maxim Integrated Products |
| 文件頁數： | 4/20頁 |
| 文件大小： | 0K |
| 描述： | EVAL KIT FOR MAX9700 |
| 產品培訓模塊： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標準包裝： | 1 |
| 放大器類型： | D 類 |
| 輸出類型： | 1-通道（單聲道） |
| 在某負載時最大輸出功率 x 通道數量： | 1.6W x 1 @ 6 歐姆 |
| 電源電壓： | 2.5 V ~ 5.5 V |
| 工作溫度： | 0°C ~ 70°C |
| 板類型： | 完全填充 |
| 已用 IC / 零件： | MAX9700，MAX9712 |
| 已供物品： | 板 |
MAX9700
1.2W, Low-EMI, Filterless,
Class D Audio Amplifier
12
______________________________________________________________________________________
the power conversion of the class D amplifier. For exam-
ple, an 8mV DC offset across an 8Ω load results in 1mA
extra current consumption in a class AB device. In the
class D case, an 8mV offset into 8Ω equates to an addi-
tional power drain of 8W. Due to the high efficiency of
the class D amplifier, this represents an additional quies-
cent-current draw of 8W/(VDD/100
η), which is on the
order of a few microamps.
Input Amplifier
Differential Input
The MAX9700 features a differential input structure,
making it compatible with many CODECs, and offering
improved noise immunity over a single-ended input
amplifier. In devices such as cellular phones, high-fre-
quency signals from the RF transmitter can be picked
up by the amplifier’s input traces. The signals appear at
the amplifier’s inputs as common-mode noise. A differ-
ential input amplifier amplifies the difference of the two
inputs; any signal common to both inputs is canceled.
Single-Ended Input
The MAX9700 can be configured as a single-ended
input amplifier by capacitively coupling either input to
GND and driving the other input (Figure 6).
DC-Coupled Input
The input amplifier can accept DC-coupled inputs that
are biased within the amplifier’s common-mode range
(see the
Typical Operating Characteristics). DC cou-
pling eliminates the input-coupling capacitors, reducing
component count to potentially one external component
(see the
System Diagram). However, the low-frequency
rejection of the capacitors is lost, allowing low-frequen-
cy signals to feedthrough to the load.
Component Selection
Input Filter
An input capacitor, CIN, in conjunction with the input
impedance of the MAX9700 forms a highpass filter that
removes the DC bias from an incoming signal. The AC-
coupling capacitor allows the amplifier to bias the sig-
nal to an optimum DC level. Assuming zero source
impedance, the -3dB point of the highpass filter is
given by:
Choose CIN so f-3dB is well below the lowest frequency
of interest. Setting f-3dB too high affects the low-fre-
quency response of the amplifier. Use capacitors
whose dielectrics have low-voltage coefficients, such
as tantalum or aluminum electrolytic. Capacitors with
high-voltage coefficients, such as ceramics, may result
in increased distortion at low frequencies.
Other considerations when designing the input filter
include the constraints of the overall system and the
actual frequency band of interest. Although high-fidelity
audio calls for a flat gain response between 20Hz and
20kHz, portable voice-reproduction devices such as
cellular phones and two-way radios need only concen-
trate on the frequency range of the spoken human
voice (typically 300Hz to 3.5kHz). In addition, speakers
used in portable devices typically have a poor response
below 150Hz. Taking these two factors into considera-
tion, the input filter may not need to be designed for a
20Hz to 20kHz response, saving both board space and
cost due to the use of smaller capacitors.
Output Filter
The MAX9700 does not require an output filter. The
device passes FCC emissions standards with 100mm
of unshielded speaker cables. However, output filtering
can be used if a design is failing radiated emissions
due to board layout or cable length, or the circuit is
near EMI-sensitive devices. Use an LC filter when radi-
ated emissions are a concern, or when long leads are
used to connect the amplifier to the speaker.
Supply Bypassing/Layout
Proper power-supply bypassing ensures low-distortion
operation. For optimum performance, bypass VDD to
GND and PVDD to PGND with separate 0.1F capaci-
tors as close to each pin as possible. A low-imped-
ance, high-current power-supply connection to PVDD is
assumed. Additional bulk capacitance should be
added as required depending on the application and
power-supply characteristics. GND and PGND should
be star connected to system ground. Refer to the
MAX9700 evaluation kit for layout guidance.
f
RC
dB
IN IN
=
3
1
2
π
Figure 6. Single-Ended Input
1
μF
IN+
IN-
1
μF
SINGLE-ENDED
AUDIO INPUT
MAX9700
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相關代理商/技術參數 |
參數描述 |
|---|---|
| MAX9700CEBC | 制造商:Maxim Integrated Products 功能描述:1.2W LOW EMI FILTERLESS CLASS D - Rail/Tube |
| MAX9700CEBC+ | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX9700CEBC+T | 功能描述:音頻放大器 1.2W L-EMI Filterles Class D Audio Amp RoHS:否 制造商:STMicroelectronics 產品: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: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| MAX9700CEBC-T | 功能描述:音頻放大器 RoHS:否 制造商:STMicroelectronics 產品: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: 安裝風格:SMD/SMT 封裝 / 箱體:TQFP-64 封裝:Reel |
| MAX9700CETB | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
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