參數(shù)資料
型號(hào): MAX4365
廠商: Maxim Integrated Products, Inc.
英文描述: 1.4W and 1W, Ultra-Small, Audio Power Amplifiers with Shutdown
中文描述: 1.4W及1W、超小型、音頻功率放大器,帶有關(guān)斷
文件頁數(shù): 10/15頁
文件大?。?/td> 682K
代理商: MAX4365
M
The increase in power delivered by the BTL configura-
tion directly results in an increase in internal power dis-
sipation over the single-ended configuration. The
maximum power dissipation for a given V
CC
and load is
given by the following equation:
If the power dissipation for a given application exceeds
the maximum allowed for a given package, reduce
V
CC
, increase load impedance, decrease the ambient
temperature or add heat sinking to the device. Large
output, supply, and ground PC board traces improve
the maximum power dissipation in the package.
Thermal-overload protection limits total power dissipa-
tion in the MAX4364/MAX4365. When the junction tem-
perature exceeds +160
°
C, the thermal protection
circuitry disables the amplifier output stage. The ampli-
fiers are enabled once the junction temperature cools
by 15
°
C. This results in a pulsing output under continu-
ous thermal overload conditions as the device heats
and cools.
The MAX4365 QFN package features an exposed ther-
mal pad on its underside. This pad lowers the thermal
resistance of the package by providing a direct heat
conduction path from the die to the PC board. Connect
the exposed thermal pad to circuit ground by using a
large pad, ground plane, or multiple vias to the ground
plane.
Efficiency
The efficiency of the MAX4364/MAX4365 is calculated
by taking the ratio of the power delivered to the load to
the power consumed from the power supply. Output
power is calculated by the following equations:
where V
PEAK
is half the peak-to-peak output voltage. In
BTL amplifiers, the supply current waveform is a full-
wave rectified sinusoid with the magnitude proportional
to the peak output voltage and load. Calculate the sup-
ply current and power drawn from the power supply by
the following:
The efficiency of the MAX4364/MAX4365 is:
The device efficiency values in Table 1 are calculated
based on the previous equation and do include the
effects of quiescent current. Note that efficiency is low
at low output-power levels, but remains relatively con-
stant at normal operating, output-power levels.
Component Selection
Gain-Setting Resistors
External feedback components set the gain of both
devices. Resistors R
F
and R
IN
(see
Typical Application
Circuit/Functional Diagram
) set the gain of the amplifier
as follows:
Optimum output offset is achieved when R
F
= 20k
.
Vary the gain by changing the value of R
IN
. When using
the MAX4364/MAX4365 in a high-gain configuration
(greater than 8V/V), a feedback capacitor may be
required to maintain stability (see Figure 2). C
F
and R
F
limit the bandwidth of the device, preventing high-fre-
quency oscillations. Ensure that the pole created by C
F
and R
F
is not within the frequency band of interest.
Input Filter
The input capacitor (C
IN
), in conjunction with R
IN
forms
a highpass filter that removes the DC bias from an
incoming signal. The AC-coupling capacitor allows the
amplifier to bias the signal to an optimum DC level.
Assuming zero source impedance, the -3dB point of
the highpass filter is given by:
Choose R
IN
according to the
Gain-Setting Resistors
section. Choose C
IN
such that f
-3dB
is well below the
lowest frequency of interest. Setting f
-3dB
too high
affects the low-frequency response of the amplifier. Use
capacitors whose dielectrics have low-voltage coeffi-
=
3
1
2
dB
R C
π
A
R
R
VD
F
IN
= ×
2
η
π
=
=
P
P
P
V
OUT
IN
OUT L
2
2
CC
P
V
V
π
R
IN
CC
PEAK
L
=
2
I
V
π
R
CC
PEAK
L
=
2
P
V
R
OUT
PEAK
2
L
=
2
P
V
π
R
DISS MAX
(
CC
2
L
)
=
2
2
1.4W and 1W, Ultra-Small, Audio Power
Amplifiers with Shutdown
10
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MAX4365EGA 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
MAX4365ETA 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
MAX4365ETA+ 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述:
MAX4365ETA+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
MAX4365ETA-T 功能描述:音頻放大器 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