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| 型号： | MAX9708ETN+D |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 7/22页 |
| 文件大小： | 0K |
| 描述： | IC AMP AUDIO PWR 42W STER 56TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 37 |
| 类型： | D 类 |
| 输出类型： | 1-通道（单声道）或 2-通道（立体声） |
| 在某负载时最大输出功率 x 通道数量： | 42W x 1 @ 4 欧姆; 21W x 2 @ 8 欧姆 |
| 电源电压： | 10 V ~ 18 V |
| 特点： | 消除爆音，差分输入，静音，短路和热保护，关机 |
| 安装类型： | 表面贴装 |
| 供应商设备封装： | 56-TQFN-EP（8x8） |
| 封装/外壳： | 56-WFQFN 裸露焊盘 |
| 包装： | 管件 |
| 产品目录页面： | 1392 (CN2011-ZH PDF) |
MAX9708
20W/40W, Filterless, Spread-Spectrum,
Mono/Stereo, Class D Amplifier
15
Maxim Integrated
Sharing Input Sources
In certain systems, a single audio source can be
shared by multiple devices (speaker and headphone
amplifiers). When sharing inputs, it is common to mute
the unused device, rather than completely shutting it
down, preventing the unused device inputs from dis-
torting the input signal. Mute the MAX9708 by driving
MUTE low. Driving MUTE low turns off the Class D out-
put stage, but does not affect the input bias levels of
the MAX9708.
Frequency Synchronization
The MAX9708 outputs up to 21W on each channel in
stereo mode. If higher output power or a 2.1 solution is
needed, two MAX9708s can be used. Each MAX9708
is synchronized by connecting SYNCOUT from the first
MAX9708 to SYNCIN of the second MAX9708 (see
Figure 5).
Supply Bypassing/Layout
Proper power-supply bypassing ensures low-distortion
operation. For optimum performance, bypass PVDD to
PGND with a 0.1F capacitor as close to each PVDD
pin as possible. A low-impedance, 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. For the TQFN package, solder the exposed
paddle (EP) to the ground plane using multiple-plated
through-hole vias. The exposed paddle must be sol-
dered to the ground plane for rated power dissipation
and good ground return. Use wider PC board traces to
lower the parasitic resistance for the high-power output
pins (OUTR+, OUTR-, OUTL+, OUTL-). Refer to the
MAX9708 Evaluation Kit for layout guidance.
Thermal Considerations
Class D amplifiers provide much better efficiency and
thermal performance than a comparable Class AB
amplifier. However, the system’s thermal performance
must be considered with realistic expectations along
with its many parameters.
Continuous Sine Wave vs. Music
When a Class D amplifier is evaluated in the lab, often
a continuous sine wave is used as the signal source.
While this is convenient for measurement purposes, it
represents a worst-case scenario for thermal loading
on the amplifier. It is not uncommon for a Class D
amplifier to enter thermal shutdown if driven near maxi-
mum output power with a continuous sine wave. The
PC board must be optimized for best dissipation (see
the
PC Board Thermal Considerations section).
Audio content, both music and voice, has a much lower
RMS value relative to its peak output power. Therefore,
while an audio signal may reach similar peaks as a
continuous sine wave, the actual thermal impact on the
Class D amplifier is highly reduced. If the thermal per-
formance of a system is being evaluated, it is important
to use actual audio signals instead of sine waves for
testing. If sine waves must be used, the thermal perfor-
mance will be less than the system’s actual capability
for real music or voice.
PC Board Thermal Considerations
The exposed pad is the primary route for conducting
heat away from the IC. With a bottom-side exposed
pad, the PC board and its copper becomes the primary
heatsink for the Class D amplifier. Solder the exposed
pad to a copper polygon. Add as much copper as pos-
sible from this polygon to any adjacent pin on the Class
D amplifier as well as to any adjacent components, pro-
vided these connections are at the same potential.
These copper paths must be as wide as possible. Each
of these paths contributes to the overall thermal capa-
bilities of the system.
The copper polygon to which the exposed pad is
attached should have multiple vias to the opposite side
of the PC board, where they connect to another copper
polygon. Make this polygon as large as possible within
the system’s constraints for signal routing.
Additional improvements are possible if all the traces
from the device are made as wide as possible.
Although the IC pins are not the primary thermal path
out of the package, they do provide a small amount.
The total improvement would not exceed approximately
10%, but it could make the difference between accept-
able performance and thermal problems.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX9708ETN-T | 制造商:Maxim Integrated Products 功能描述:20W/40W FILTERLESS, SPREAD-SPECTRUM, MONO/STE - Tape and Reel |
| MAX9708EVKIT | 功能描述:音频放大器 Evaluation Kit for the MAX9708 RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel |
| MAX9709ECB+ | 制造商:Maxim Integrated Products 功能描述:AUD AMP SPKR 1CH MONO/2CH STEREO 50W/29W CLS-D 64TQFP EP - Rail/Tube |
| MAX9709ECB+T | 制造商:Maxim Integrated Products 功能描述:AUD AMP SPKR 1CH MONO/2CH STEREO 50W/29W CLS-D 64TQFP EP - Tape and Reel |
| MAX9709ETN | 功能描述:音频放大器 RoHS:否 制造商:STMicroelectronics 产品:General Purpose Audio Amplifiers 输出类型:Digital 输出功率: THD + 噪声: 工作电源电压:3.3 V 电源电流: 最大功率耗散: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:TQFP-64 封装:Reel |
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